Adds theme selector to switch between light and dark theme variants

[ashutoshgngwr]

Changes

Also adds light app theme

Testing

• Tested on a physical device
• Added or modified unit test cases

Others

• Fixes #0
• Connects #0

[codecov]

Codecov Report

Merging #103 into master will increase coverage by 1.03%.
The diff coverage is 89.47%.

@@             Coverage Diff              @@
##             master     #103      +/-   ##
============================================
+ Coverage     77.53%   78.57%   +1.03%     
- Complexity       96      102       +6     
============================================
  Files            11       11              
  Lines           650      686      +36     
  Branches         81       89       +8     
============================================
+ Hits            504      539      +35     
- Misses           84       85       +1     
  Partials         62       62

Impacted Files	Coverage Δ	Complexity Δ
...ava/com/github/ashutoshgngwr/noice/MainActivity.kt	82.55% <89.47%> (+1.67%)	17 <5> (+6)	⬆️
...ashutoshgngwr/noice/fragment/SleepTimerFragment.kt	90% <0%> (+4.51%)	8% <0%> (ø)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7852744...5745198. Read the comment docs.