Fix #4835: Add the ability to remove site-specific web data

[kylehickinson]

Summary of Changes

This pull request fixes #4835

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()

Test Plan:

• Visit websites
• Visit Manage Website Data (Settings > Brave Shields & Privacy > Manage Website Data)
• Verify website data appears
• Test "Remove All"
• Verify empty state
• Close and re-visit websites but do something on one that saves a cookie such as login
• Verify new data appears
• Tap the edit button, verify that single selection changes remove button text to "Remove" and selecting more than 1 changes it to "Remove N Records" where N is the number of selected records
• Verify tapping remove on those websites removes them from the list and refresh the web page that was logged in (or had some cookie stored) and verify you are no longer logged in (or cookie is erased)
• Use the search functionality to limit the number of items
• Verify tapping "Remove All" while searching only removes visible/filtered records

Screenshots:

Main	Edit Mode	Edit Mode Selected

Empty State	Filter

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable).
• Issue and pull request is assigned to a milestone (should happen at merge time).

[duaneking]

Thank You!