[chrEx] remove all instances of lastTimestampSynced (20 mins) about porno-_porn_blocker HOT 1 OPEN

i can do two things:

1. check if lastTimestampSynced exists in user storage. if so, delete it.
2. check if there are values in storage that aren't user redirect links, user custom ban list, and user redirection history. if so, delete those values. this way allows me to avoid writing custom data removal logic in case im in a similar situation in the future.

to do number 2, it might be easier to first move user redirect links into their own object and then user ban list into its own object. redirection history is already a list so its fine as is.

from porno-_porn_blocker.