Settings: remove taps to become a developer

Developer settings are enabled by default, so having this "feature"
in the Settings app is pointless and annoying. Remove it to improve
the UX.

PS2: Remove some strings too

Change-Id: I87fc6aadb8969717ea55df345ffab6f8ee397882
Signed-off-by: Rohan Mathur <rohanmathur34@gmail.com>