Format hashes input

[victorgcramos]

The "Search for hashes" input tells users that it accepts multiple hashes. However, if users type hashes with blank spaces,
the form will redirect to https://timestamp.decred.org/results#hashes=<hash-1>,%20<hash-2>, which throws a JSON parse error and enters on an infinite loading state, as described below:

Unhandled Promise Rejection: SyntaxError: JSON Parse error: Unexpected identifier "Invalid"

I think we should format these inputs (or validate them), so users don't get redirected to a loading page.

[tiagoalvesdulce]

this behavior will be changed in the redesign

[tiagoalvesdulce]

Not needed after #151