Fixes#3540.
Merges all relevant changes from Keyman Configuration xml folder into
the FirstVoices Keyboards xml folder.
Adds support for enabling/disabling keyboards for FirstVoices Keyboards.
Renames from Keyman Desktop for FirstVoices to Keyman for FirstVoices.
While it might be nice to add the tag to versions in filenames, this
creates a lot of work on the website where we make some filename
assumptions. So, this PR winds that detail of filename changes back,
and renames copydev.in to download.in to make it consistent with the
other download.in files.
Release build executables should have 3 component version numbers with
the version tag appended, e.g. keymandesktop-14.0.155-alpha-local.exe.
Coming later, rename keymandesktop-version.exe to keyman-version.exe.
Moves all version construction to use VERSION.md and
TIER.md and reduces intermediate file usage, so we can
present sensible versions across the project.
