luci-mod-status: add simple filtering for connections

luci-mod-status: add simple filtering for connections

This commit adds a simple filtering input text into the connections status page. You can type some filtering like:
- '100.15' -> Will show only connections that include this '100.15' onto the IP.
- 'UDP 100.15' -> Will show only UDP connections that include this '100.15' onto the IP.
- ':443' -> Will show only connections that use the port 443 as source or destination.

You can use a part of the IP or part of the name if the DNS resolution button is enabled.

It's a very simple filter that can grow in the future if it deserves some interest, maybe adding some regular expression support.

Signed-off-by: Miguel Angel Mulero Martinez <migmul@gmail.com>