feat(developer): add kmx metadata to kmxplus compiles

Fixes #7273.

Adds 4 kmx system stores to allow existing configuration tools to load
and process KMXPlus files without modification:

* `TSS_NAME` (first `<name>`)
* `TSS_COMPILEDVERSION` (only if `options.addCompilerVersion == true`)
* `TSS_KEYBOARDVERSION` (from `<version number>`)
* `TSS_TARGETS` (currently always 'desktop', will later include more
  targets)

In order for `TSS_COMPILEDVERSION` to be handled correctly, needed to
plumb in the new `CompilerOptions` interface. This could be a separate
PR, but the changes are not huge, so opted to append the changes here.

Updates related tests and fixtures. Refactored some of the e2e helpers
into helpers/index.ts for use with the metadata-compiler tests.