[Mouse Without Borders] - refactoring "Common" classes

[mikeclayton]

Description of the new feature / enhancement

As a precursor to #34126 (Integrate Mouse Jump with Mouse Without Borders) I've spoken with @crutkas and @ethanfangg about doing some mechanical refactoring to break the large "Common" class into multiple smaller classes as general maintenance / housekeeping work.

Each "Common.*.cs" partial file will be turned into a separate static class so as to reduce the scope of the private members inside them and make it easier / safer to perform other changes (e.g. integration with Mouse Jump) at a later date.

Changes to each "Common.*.cs" file will be submitted as a separate PR.

Scenario when this would be used?

No change in functionality - this is a refactoring / maintenance change designed to make some future work easier / safer to implement.

Supporting information

No response

[crutkas]

Make it so

[crutkas]

@mikeclayton isn't this #35156 or is there more

[mikeclayton]

@crutkas - There's more PRs to come - there's about a dozen "Common.*.cs" classes and we talked about moving cautiously and doing one file at a time so as not to break anything.

I've been trying to get the Mouse Jump style work over the line in #35521 - once that's done I can spend a bit more time on Mouse Without Borders (I've got a second refactor lined up but I've not had time to go through the regression tests yet)...