feat(ui): updates to dark mode logic

[zackbcom]

Changes

• Updates to dark mode logic to have 3 options, System defined, Dark and, Light.
• Reused bool in the settings to use null as system defined.
• Created listener for changes to system dark mode. Works on mac when selecting system theme.
• Added button toggle to support the 3 cases.

TODO

• [ ] Need to figure out what to do with the login checkbox.
  • [ ] Might be able to look into a indeterminate state for system.
  • [ ] Replace with button stack
  • [ ] Remove and use system default, update in settings.

Testing Artifacts

• After
  • 

[coveralls]

Pull Request Test Coverage Report for Build 9362246394

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 21.163%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/stores/base.js	0	1	0.0%
<!--	Total:	0	1	0.0%	-->

Totals
Change from base Build 9347582370:	0.0%
Covered Lines:	3899
Relevant Lines:	19593

---

💛 - Coveralls