build: define upstream-repos in modules-file

Switch from defining the upstream-repos and relating commit in config.mk
and feeds.conf to define all in the modules-file.
The modules-files is the real file used by the build-system to setup the
working checkout. It originates from the Gluon-buildsystemand some
documentation is avail at https://gluon.readthedocs.io/en/latest/dev/build.html

This also relates to
* PR freifunk-berlin#781
* Issue freifunk-berlin#780
* Issue freifunk-berlin#772

config.mk

@@ -2,7 +2,5 @@
 SHELL:=$(shell which bash)
 TARGET=ar71xx-generic
 PACKAGES_LIST_DEFAULT=notunnel tunnel-berlin-tunneldigger manual
-OPENWRT_SRC=https://git.openwrt.org/openwrt/openwrt.git
-OPENWRT_COMMIT=55312cc2025035cc1361417eecfacb4dae46bb67
 SET_BUILDBOT=env
 MAKE_ARGS=V=s

modules

@@ -0,0 +1,27 @@
+OPENWRT_REPO=https://git.openwrt.org/openwrt/openwrt.git
+OPENWRT_COMMIT=55312cc2025035cc1361417eecfacb4dae46bb67
+OPENWRT_BRANCH=openwrt-19.07
+
+PACKAGES_PACKAGES_REPO=https://github.com/openwrt/packages.git
+PACKAGES_PACKAGES_COMMIT=059e949eec0170a95a6305c75316f32fac67244d
+PACKAGES_PACKAGES_BRANCH=openwrt-19.07
+
+PACKAGES_LUCI_REPO=https://github.com/openwrt/luci.git
+PACKAGES_LUCI_COMMIT=eeba108ed638e4577eca1ea540ab685b3f171cca
+PACKAGES_LUCI_BRANCH=openwrt-19.07
+
+PACKAGES_FREIFUNK_REPO=https://github.com/freifunk/openwrt-packages.git
+PACKAGES_FREIFUNK_COMMIT=73454e6fe1bdc902c69ca0079d979fdb94d6fb1f
+PACKAGES_FREIFUNK_BRANCH=openwrt-19.07
+
+PACKAGES_ROUTING_REPO=https://github.com/openwrt-routing/packages.git
+PACKAGES_ROUTING_COMMIT=9f21b212ef56be257c8d5012f41d55cf2e316f93
+PACKAGES_ROUTING_BRANCH=openwrt-19.07
+
+PACKAGES_PACKAGES_BERLIN_REPO=https://github.com/freifunk-berlin/firmware-packages.git
+PACKAGES_PACKAGES_BERLIN_COMMIT=a96afe33df8a371dc7b9657b874db92a022c03a9
+
+PACKAGES_PACKAGES_GLUON_REPO=https://github.com/freifunk-gluon/packages.git
+PACKAGES_PACKAGES_GLUON_COMMIT=033401c18ecbf5073f5330b4462af6e450e358ff
+
+GLUON_FEEDS='packages luci freifunk routing packages_berlin packages_gluon'