luci-mod-status: status/routing support for pbr

Provide comprehensive status information for routing.
Rename the "Status > Routes" page to "Status > Routing".
Unify sorting for the "Status" and "Network" menus.
Add tabs for IPv4 and IPv6 and reorganize the contents.
Display routing rules and their priorities for each protocol.

Policy-based routing is an increasingly popular problem.
Netifd natively supports policy-based routing:
* The interface-specific options "ip4table" and "ip6table".
* The routing rules using the "rule" and "rule6" sections.
LuCI is missing the information about routing rules.

Signed-off-by: Vladislav Grigoryev <vg.aetera@gmail.com>