Updates Keyman for Windows and Keyman Developer sources so that they
build under Delphi 10.4. No validation has been performed to ensure that
there are no other issues. The intent here is to get a baseline build
working.
Note also IMSample.vcxproj which has its WinSDK version updated for
VS2019.
We no longer need to backup debug files as they are saved to the symbol
store during a release build. This reduces the amount of storage
required for a release build and should speed up the build also.
Also fixes the broken build where backup had not been updated for the
new consistent build paths.
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.