fixes #11120 - migrate websockets setting when readonly in settings.yaml

fixes #11121 - initialise websockets_encrypt after dependencies

When settings.yaml (SETTINGS) is used to set websockets_encrypt to true,
the key and cert need to be initialised first for its key/cert
validation to pass.

Fixes #9603 - fixed websockets_* set of settings

fixes #10959 - gravatar should be opt-in not opt-out

Fixes #8525 - Rename "Mail" to "Email" in user preferences

Fixes #10337 - Added setting out of sync duration

Fixes #8566 - reorganized settings categories

Fixes #10194 - help text for token_duration setting

fixes #8331 - provide some tools for filtering mail

Refs #3809 - Remove cops for empty lines