Fix vulnerabilities with npm audit fix

See merge request csar9407/gitsearch!3

Disable registration

See merge request csar9407/gitsearch!4

Clickable search info

See merge request csar9407/gitsearch!2

When clicking a local filter item
only its value is interesting.

Previously only the space taken up
by a filter item's name (e.g the name of the
repo "foo") was clickable.

Now the entire area highlighted on mouseover
can be clicked.

Instead of filtering by a single value,
use sets for each category.
Display results iff they match any set element
in all non-empty sets.