AndroidX Preference, AlertDialog improvements, etc.

[TacoTheDank]

1st commit

• Delete unnecessary files

2nd commit

• Update gradle wrapper to 7.2 using git bash

3rd commit

• Clean up build gradles
• Organize dependencies

4th commit

• Update AppCompat 1.3.0 -> 1.3.1 (changelog)
• Update Android Gradle Plugin 4.2.2 -> 7.0.3 (changelog)
• Update GMS 4.3.8 -> 4.3.10 (changelog) and (changelog)
• Update firebase-crashlytics-gradle 2.6.1 -> 2.7.1 (changelog) and (changelog)

5th commit

• Preliminary reformatting of general_preferences.xml

6th commit

• Migrate to AndroidX Preference
• Use FragmentContainerView for SettingsActivity layout
• Delete unused display_preferences.xml
• Replace CheckBoxPreference with SwitchPreferenceCompat (material guidelines recommend using switches over checkboxes)
• Don't reserve icon space (this is to remove the unnecessary padding at the beginning of settings using AndroidX Preference)

7th commit

• I've refactored the PreferenceHelper to use a single sharedPreferences object initialized on app launch
  • No more passing a bunch of unnecessary contexts around.
  • No more unnecessary operations where we create a brand new PreferenceManager.getDefaultSharedPreferences instance any time a key needs to be accessed.
• Give ListPreferences unique keyValues

8th commit

• Migrate AlertDialogs to AppCompat
• Clean them up

9th commit

• Enable viewbinding
• Improve layout of the AlertDialogs that use EditText instances as their views; here's how they changed

Before	After

[richsmith]

Hi @TacoTheDank . Thanks for this PR. Even though I haven't merged it, I've gradually adopted a lot of the ideas in it.