chore(common/core/desktop): Improve meson build file 🏗️

We are not able to use VS 2022 yet because it doesn't provide
`vcvarsall.bat`, but this change at least allows to build with an older
VS version even if VS 2022 is installed.

Thanks @eli-schwartz for the suggestions (in #5797)!

Unfortunately we currently still have to support meson 0.45
(because that's what ships with Ubuntu 18.04), so we can't
implement everything suggested.

Also, newer meson versions always assume utf-8, but until we
can assume at least version 0.60 of meson we'll have to
explicitly specify the encoding, otherwise at least some tests
will fail.

chore: merge beta changes to alpha B15S4

chore(windows): Update license date

fix(web): caps state tracking for touch

fix(developer): warn on ncaps usage inconsistency

fix(web): subkey touch position after scroll

fix(android/engine): Activate menu on globe longpress before release

feat(common): zip and index keyboard artifacts

auto: increment beta version to 15.0.213

fix(android/engine): Test fileVersion during package install

chore(linux): Fix lintian warnings

fix(common): allow custom keyboard builds

Co-authored-by: Marc Durdin <marc@durdin.net>

auto: increment beta version to 15.0.212

Don't specify wine as kmcomp launcher if a custom kmcomp is provided on
the command line.

This allows for custom builds of keyboards, e.g. where a keyboard is
manually constructed for testing purposes.

fix(windows): add null pointer checks imsample keyboard

chore(common): cleanup sh global color variables

The Caps Lock change I made in the previous commit broke
desktop Caps Lock handling. The fix was a little more
convoluted. Turns out that _UpdateVKShift is also pretty
crufty. I simplified it, removing dead code.

Selecting the new Caps Lock `caps` layer was not correctly setting the
layer state in the key event to `caps`, which caused Caps Lock rules
to fail to match.

fix(oem/fv/android): Check keyboard exists before registering a model