hydra-server: add `limit` parameter to the `search` path

Dependencies

• [2] WUCOEIFA Search: Limit the number of results
• [3] EJ7C77C3 Allow searching for store and drv paths. Only does a complete match to reduce load on database.
• [4] UICHT2PS Add a search feature
• [*] J5UVLXOK * Start of a basic Catalyst web interface.

Change contents

• replacement in src/lib/Hydra/Controller/Root.pm at line 394
  [2.1]→[2.1:31](∅→∅)
  − $c->stash->{limit} = 500;
  [2.1]

  [3.294]
  + my $limit = trim $c->request->params->{"limit"};

  + if ($limit eq "") {

  + $c->stash->{limit} = 500;

  + } else {

  + $c->stash->{limit} = $limit;

  + }