[WIP] Completely rebuild the app in QML and overhaul the codebase

This commit will shred every speck of Jekyll out of the welcome
app, replacing it with a nice QML interface. While I'm not going
for a pixel-perfect recreation of the app, I'm trying to get a
UI that looks mostly the same as the Jekyll version.

As part of the rewrite, I'm overhauling the codebase to use best
practices for modern Qt and open-source projects in general. This
includes adding a .clang-format file to keep the code looking nice.

.clang-format

@@ -0,0 +1,135 @@
+---
+Language:        Cpp
+BasedOnStyle:  LLVM
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignArrayOfStructures: None
+AlignConsecutiveMacros: false
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlines: false
+AlignOperands:   true
+AlignTrailingComments: false
+AllowAllArgumentsOnNextLine: true
+AllowAllConstructorInitializersOnNextLine: false
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: Never
+AllowShortEnumsOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortLambdasOnASingleLine: All
+AllowShortIfStatementsOnASingleLine: Never
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: Yes
+BinPackArguments: false
+BinPackParameters: false
+#BitFieldColonSpacing: Both
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterCaseLabel:  true
+  AfterClass:      true
+  AfterControlStatement: true
+  AfterEnum:       true
+  AfterFunction:   true
+  AfterNamespace:  true
+  AfterStruct:     true
+  AfterUnion:      true
+  AfterExternBlock: true
+  BeforeCatch:     true
+  BeforeElse:      true
+  BeforeLambdaBody: false
+  BeforeWhile: false
+  IndentBraces:    false
+  SplitEmptyFunction: false
+  SplitEmptyRecord: false
+  SplitEmptyNamespace: false
+BreakBeforeBinaryOperators: None
+BreakBeforeInheritanceComma: false
+BreakInheritanceList: BeforeColon
+BreakBeforeTernaryOperators: false
+BreakConstructorInitializersBeforeComma: false
+BreakConstructorInitializers: BeforeColon
+BreakAfterJavaFieldAnnotations: false
+BreakStringLiterals: true
+ColumnLimit:     125
+CompactNamespaces: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DeriveLineEnding: false
+DerivePointerAlignment: false
+DisableFormat:   false
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: true
+ForEachMacros:
+  - foreach
+  - Q_FOREACH
+  - BOOST_FOREACH
+#IncludeBlocks: Regroup
+IncludeCategories:
+  - Regex:           '^"(Q|Qt)/'
+    Priority:        1
+  - Regex:           '.*'
+    Priority:        2
+#IndentCaseBlocks: false
+IndentCaseLabels: false
+#IndentExternBlocks: true
+IndentGotoLabels: false
+IndentPPDirectives: BeforeHash
+IndentWidth:     4
+IndentWrappedFunctionNames: true
+#InsertTrailingCommas: false
+JavaScriptQuotes: Leave
+JavaScriptWrapImports: true
+KeepEmptyLinesAtTheStartOfBlocks: false
+LambdaBodyIndentation: Signature
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: All
+ObjCBinPackProtocolList: Auto
+ObjCBlockIndentWidth: 4
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: false
+PackConstructorInitializers: Never
+PenaltyBreakAssignment: 2
+PenaltyBreakBeforeFirstCallParameter: 19
+PenaltyBreakComment: 0
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 10
+PenaltyBreakTemplateDeclaration: 100
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 10000000
+PointerAlignment: Right
+ReflowComments:  true
+SortIncludes:    true
+SortUsingDeclarations: true
+SpaceAfterCStyleCast: false
+SpaceAfterLogicalNot: false
+SpaceAfterTemplateKeyword: false
+#SpaceAroundPointerQualifiers: Before
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+#SpaceBeforeParens: ControlStatementsExceptForEachMacros
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceInEmptyBlock: false
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles:  false
+SpacesInConditionalStatement: false
+SpacesInContainerLiterals: false
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+SpaceBeforeSquareBrackets: false
+Standard:        Latest
+StatementMacros:
+  - Q_UNUSED
+  - QT_REQUIRE_VERSION
+TabWidth:        4
+UseCRLF:         false
+#UseTab:          AlignWithSpaces

data/qrc/ThemedButton.qml

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+import QtQuick
+import QtQuick.Controls
+
+Button {
+    id: buttonRoot
+
+    required property color themeColor
+
+    implicitWidth: 200
+    implicitHeight: 40
+    icon.height: font.pixelSize
+    icon.color: palette.text
+
+    background: Rectangle {
+        border.color: (buttonRoot.pressed || hh.hovered) ? Qt.darker(themeColor, 1.4) : themeColor
+        color: (buttonRoot.pressed || hh.hovered) ? Qt.darker(themeColor, 1.4) : themeColor
+        radius: 5
+        width: buttonRoot.width
+        height: buttonRoot.height
+
+        Behavior on color { ColorAnimation { duration: 100 } }
+    }
+
+    HoverHandler {
+        id: hh
+        cursorShape: Qt.PointingHandCursor
+    }
+}