Allow giving roles on survey for answer permission

Admin people have roles on survey, instead of questionnaires, and they
still should be allowed to modify answer. In order to do so, an answer
must consider both contexts: survey and questionnaire
Update activity::record_id from smallint to int
Change an icon in activity
Correct estimates table headers
Move user activity to user page #3009
Show confirmation when role was requested
Link to users when granting access
Show user gravatar in admin