First half of #9999.

Adds support for normalization (to NFD) of input app context into the
cached context. The keyboard processor will work with the NFD cached
context.

Adds unit tests for the normalization as part of the LDML keyboard
processor test suite.

TODO:
* Comparing modified cached context to app context to determine the
  transform required to send to the app
* Handling illegal unicode and unpaired surrogates on input context

Adds the application context member of state and a corresponding,
failing unit test, which starts the process of verifying the handling
of the application context.

Fixes #10365.

Adds a `km_core_state_context_debug` function that returns a km_core_cp
string containing the current cached or intermediate context. The
function must be used only for debug logging purposes -- the string is
not intended to parsed for other purposes and the format may change in
the future.

This commit adds the function and corresponding unit tests. Subsequent
commits will update existing context debug functions in various engines
to use this API endpoint instead.

auto: increment master version to 17.0.244

refactor(linux): Use `km_core_state_context_set_if_needed`

chore(linux): fix GHA packaging

fix(ios): use safe area to position Keyman menu correctly

refactor(core): use `km_core_state_context_clear` where possible

fix(developer): test-page model loading

Relates to #10365.

Use `km_core_state_context_clear()` instead of `km_core_context_clear()`
as part of eliminating use of `km_core_state_context()`.

fix(web): prediction time-limiter issues, performance 📜

chore(common): Update crowdin strings for French, German, Spanish (Latin America)

chore(core): split out some files 🙀

auto: increment master version to 17.0.243

- reapply 0d9f543a code review comments

#10320

- reapply 0d9f543a code review comments

chore(common): builder action launch typos

fix(developer): new file support for project 2.0

fix(developer): cleanly handle filling a new osk file from layout

fix(developer): remove unused tools/customise menu

fix(windows): serve images for readme files in Keyboard Install

Follow on from #10329.

- cleanup NFC code later if it's entirely unneeded.

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

auto: increment master version to 17.0.242

Also update comment on `km_core_state_context_set_if_needed` to make it
clearer that it's expecting a UTF-16 string.

Closes #10212.