Localization support

Localization support was psuedo-dropped for 2.0 due to time purposes. Users can always create their own UI, of course, but our built-in UIs should support localization. It would also be nice if localization was supported via the core NetSparkle DLL rather than being in the UI factories. (Is that possible?)

• Investigate whether moving all UI localization to the core NetSparkle is possible in a way that is .NET Framework and .NET Core compatible. We already have a Resources.resx there, so surely it should be possible?
• Move all localized strings to core NetSparkle
• Update strings based on new 2.0+ usage
• Update built-in UIs to use the new localization strings
• Test and make sure everything works
• Make sure date formats are setup properly or easily configurable for release notes (see #334)
• Short term: Make sure JA is listed in the csproj for embedded resources

Start by reviewing the existing Resources.resx, the project files containing embedded resources, and the built-in UI factories. Investigate whether shared localization can remain compatible with .NET Framework and .NET Core, and review #334 for release-note date formatting. Done means the checklist is completed, including updated strings, built-in UI usage, and tests.