[P] Address backlogs related to Updater

Description

This MR:

• Changes the string which is responsible to show Show changelog in the menu action buttons to Show release notes
• Enables updates auto-deletion preference by default

Related issues

• e/backlog#2596 (closed)
• e/backlog#2593 (closed)
• e/backlog#1218 (closed)
• e/backlog#2772 (closed)
• e/backlog#1079 (closed)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Related MRs

None

How has this been tested?

Clean flash a new build with this MR. Notice that:

• Menu now shows Show release notes in place of Show changelog
• The switch to autodelete updates once installed is now checked by default

Clean flash an old build (0.14 preferable). Build an app of Updater with this patch and push it into the system using adb. Notice that:

• Updater now shows the proper version name in the notification, update list and install screen during an update.
• Run the following commands and notice that Updater shows "New Updates Notification":
  • adb root
  • adb shell am broadcast -a android.intent.action.BOOT_COMPLETED -c android.intent.category.DEFAULT -n org.lineageos.updater/.UpdatesCheckReceiver

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules