Add 'selected' option to Select field and update specs

[Thrizian]

Introduced a 'selected' option in the Select field to specify a default value when no data is available. Updated the form partial to prioritize 'selected' over data and added related test cases to ensure correct behavior. Updated .gitignore and added .tool-versions for environment settings.

[Thrizian]

This is my first ever open source commit, So if i'm slacking somewhere. Let me know. Also i'm having trouble testing this myself because the 1.0.0.beta1 blows up for me. sassc-rails, i've created an issue for it here #2677.

Also, can i run the demo app locally to test it?

[Thrizian]

I've had another go at this. Since i figured out how to get the application up and running locally, #rtfm. I'm pretty bad at writing tests so perhaps someone can help me with writing some better coverage. But this should get us a nice start to get some more selectize functionality.

I've used the selectcontroller stimuluscontroller to handle this. We are using data attributes to get the message passed across.

This PR now adds:

• selected
• multiple
• max_items
• include_blank

Max items. Allows for selecting items up to max_items.

    kind: Field::Select.with_options(
      collection: [1,2,3,4],
      max_items: 2
    )

Multiple selecting multiple options.

    kind: Field::Select.with_options(
      collection: [1,2,3,4],
      selected: 4,
      max_items: 2
    )

Selected, allows for the selection of a specific element or multiple elements.

    kind: Field::Select.with_options(
      collection: [1,2,3,4],
      selected: 4,
    )

   kind: Field::Select.with_options(
     collection: [1,2,3,4],
     selected: [2,4],
   )

This also works with [[1, 2],[3,4],[5,6]]

   kind: Field::Select.with_options(
     collection: [[1, 2],[3,4],[5,6]],
     selected: [2,4],
   )