Now that we have the file type detection in place, we can replace
existing references to the file extensions, where possible, with the
constant declarations. While we could rely on TypeScript's typing to use
string-based values, this helps us to avoid using file extensions
directly in string transforms, regex, etc, and use the `KeymanFileTypes`
alias instead.

Note that only references in common/web, and kmc-* projects have been
touched. References in other Developer projects have not been touched,
as some of those are not yet ESM, so that needs to be addressed first.

This module is used for identification of Keyman source and binary file
formats by file extension. It is not yet appropriate to use for
constants; this will come in a future commit.

LdmlCompilerOptions is now based on the shared CompilerOptions. Also
fixes command line parameter inheritance for sub-commands.

Part 1 of the `CompilerOptions` reorg. kmc now uses `CompilerOptions`
throughout, and `CompilerBaseOptions` maps to the set of options
available to all activities.

chore(common): cleanup error handling for KmxFileReader and CompilerOptions as shared type

* Also adds info messages for scanning.

Tidies up silent vs quiet vs verbose by adding logLevel as an option.

* Notes that we need to consolidate all the various CompilerOptions
  interfaces before they get too much further out of hand.
* Cleans up a couple of other minor TODO items.

In order to match existing behaviour with the legacy KeymanWeb compiler,
we should use quoted numbers for row ids. This behaviour can probably be
changed over to the new model in the future, but for now this prevents
unit tests from causing us grief.

feat(developer): Rewrite of KeymanWeb compiler in Typescript

Co-authored-by: Joshua Horton <joshua_horton@sil.org>

Our dev env mostly assumes that build/ is for build artifacts, so this
just sidesteps issues with code search, etc.

The other glaring example of this is resources/build/ which is a _much_
more painful change, given how many scripts reference it. So not
changing that for now.

Also fixes handling of kmx errors in kmc-package.

auto: increment master version to 17.0.121

fix(android/engine): Re-enable KMManager tests

fix(linux): Fix title of reference page and links

chore(linux): Move some files to keyman-config

chore(core): look for emcc.py, not emcc