Use semantic versioning for compatibility computation

[jonsch318]

This adds a very very simple semantic versioning check for compatibilities to replace the strict compatibility matrix.
I think this is better and could alleviate some of your effort, since we trust that 2.6.6 does not change anything dramatic over 2.6.5 and users would not be annoyed on the dialog to show up

// versions precedence:
// 1. Version found in version matrix -> use that
// 2. walk patch to 0 -> if found something use that
// 3. walk minor to 0 (including patches) -> at least MIXED_COMPATIBILITY or worse
// else Unknown

Then I also added that the version setting changes background color and adds a trailing icon for the given compatibility state. The colors had to be a bit darkened to make them visible enough.

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Screenshots
Faked making 2.6.4 fully compatible.

The current version matrix would result in