Add admin and moderator indicators to the user profile

Revives !250 (closed)

The complementary BE MR is merged now.

Updated video that shows how the settings change take place: https://cl.ly/483e72275867

Screenshots of how badges look in different themes:

(Updated styling with theming support as per @hj's feedback (I used .alert with neutral gray that — the button background color that is optimized to be aligned with different themes):

• Pleroma Dark

• Pleroma Light

• Classic

• Bird

• Ir Black

• Monokai

• Mammal

• Redmond XX

• Breezy Dark

• Breezy Light

BE provides two JSON fields: role (which can be admin, moderator, or default member) and show_role. A few notes

• If the user chooses not to display role, BE doesn't include role in the JSON response when giving this user's data to other users.

• show_role is visible only to the current user and is used for toggling the parameter in the user settings UI