Fixes#10161.
Includes transition of existing options from registry to options.json,
and once options.json exists, will always read from that and ignore
registry. Was able to eliminate some of the legacy datatype usage for
several options. Reader/writer includes naive file lock retry to avoid
contention, which I am hopeful will be sufficient for our needs, given
the low chance of contention.
First part of addressing #10161 is to refactor the existing usage of the
registry values into the common KeymanDeveloperOptions unit. This was
mostly straightforward except for the changes to KeymanSentryClient,
which happens to be the most important part of this particular fix.
Fixes#10146.
Some developers may wish to stick with kpj-1.0 for now, and the prompt
to upgrade would annoying because it cannot be hidden. This resolves
that.
Note that I haven't at this point renamed UrlRenderer.pas, although it
may be worth considering in the future.
