Add personal settings for stream activities

Already has some new settings and email included, but these options are hidden
from the UI until the activities themselves are implemented.

Fix #1705
Correctly deal with empty selections and respect the setting while searching
Move checkboxes to the left and make the rows a bit higher

Fix #1705
Make the checkbox easier clickable

Fix #1705
Display success message when the setting has been saved
Change the wording a bit and highlight the keyword of the setting

Fix #1705
Extract user notification type query generation into a new method

Fix #1705
Add ability to select all rows/columns at once
Opening curl braces on previous line

Fix #1705
Add activity subjects to translation system

Fix #1726
Do not remove first activity from grouped activities

Fix #1557
Remove todo for translating the subjects

Fix #1726
Merge pull request #1728 from owncloud/issue/1557

Do not remove first activity from grouped activities
Merge pull request #1718 from owncloud/issue/1705

Add personal settings for stream activities
[tx-robot] updated from transifex
[tx-robot] updated from transifex
[tx-robot] updated from transifex
[tx-robot] updated from transifex
remove pl_PL - refs https://github.com/owncloud/core/issues/7973
Merge pull request #1727 from owncloud/issue/1726

Add activity subjects to translation system