Syncing mobile blues and greens with official design palette

Previously, we were using several different blue and green colors
none of which matched the official design palette (as used on desktop).
See: https://trello.com/c/IRqbu8p4/15-color-swatches

Not changing the red since we use that red for text color as well.

Changing link color for talk page link to normal link color as this
is not a progressive action, just a link.

Also changing border around fieldsets in Special:Preferences from
blue to gray.

Change-Id: I483d953f0626300a10db1e8662df591580809a37
Merge "Syncing mobile blues and greens with official design palette"