Add basic support for dark mode & update Swift schema.

[furby-tm]

Within this PR is support for:

• minimum, basic dark mode support (toggle-able via the View menu in the menubar).
• updated Swift schema for the replacement of Objective-C properties with the new Swift @Persisted property wrappers.

[cla-bot[bot]]

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[furby-tm]

@cla-bot check

[cla-bot[bot]]

The cla-bot has been summoned, and re-checked this pull request!

[kraenhansen]

@furby-tm could you post a few screenshots from the app when in dark mode?

[furby-tm]

Hey guys! Sorry, I'm just now getting to your response -- I've been tied down with some projects getting rolled out into production over the last couple weeks, so things have been hectic.

I had just a couple hours to spare, and spent that time trying to tone down the blinding light mode of the app, since I use it frequently, and figured my eyes could spare a break.

I realize my PR was a 0 context shove in, so I apologize for that!

To quickly summarize these changes:

I added a basic dark mode, and made some additional changes to the light mode which integrated some of the UI aspects of MongoDB Compass. The dark mode will need some cleanup since I missed a lot of the text on the tables (lots of it is looking black on black so that won't do!).

I brought in the latest changes to the realm swift generation schema, which is the removal of any/all objc boilerplate and integrated the ‘@Persisted’ swift property wrappers.

And I believe that was all. If dark mode & rolling in the latest swift schematic changes are something the realm team are looking to support I'd be happy to fixup a proper PR for your review.