Governance: change block# to time

[0xhuman]

Is your feature request related to a problem? Please describe.
When a proposal is submitted, it conveys the snapshot time(time you must stake by to participate in the vote) using the block number, which cannot be interpreted by most humans.

Describe the solution you'd like
Display the snapshot time using date/time (convert difference between current and snapshot block number to date-time). Consider displaying it like this:

Only veMOBI that was locked before block 11124711 (Wednesday 1/26 at 8:14am PST) are eligible for voting.

This will require changing what is displayed before voting (during waiting period) and once voting is started (example shown above).