CMake: Add nightly platform to build Qt with CMake master from source

Upstream CMake sometimes introduces behavior changes or breakage that
affects building Qt or user projects.

It is beneficial to catch these issues earlier, before a major / minor
CMake release is made, and before we update our provisioning scripts
to use a newer CMake.

Add a new nightly platform file, which includes all existing cmake
platform configurations, and adds the "BuildCMakeFromSources" feature
to all of them.

This feature:
- tells qtbase CI instructions to download the latest master branch
sources from the CMake repository mirror
- builds CMake from these sources
- uses this CMake to configure Qt

The nightly build will run once a week to catch potential issues
introduced in newer CMake changes.

Fixes: QTBUG-143633
Change-Id: If7223b462a437f97b9fecabb5726a5fcaab4be53
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

coin/platform_configs/nightly_build_qt_with_cmake_master.yaml

@@ -0,0 +1,11 @@
+Version: 2
+Include: [
+    cmake_platforms.yaml,
+    address_sanitizer_platforms.yaml,
+    offline_documentation.yaml
+]
+Configurations: []
+Overrides:
+-
+    Id: '.*'
+    +Features: ['BuildCMakeFromSources']