Rework inbound routing to enable CID/DID match priorities.

I would like the see 'inbound routing' provided with an ordered priority (like
outbound routing).

Why? Because currently, if an admin adds three inbound routes;

<any>/<any> -> ringgroup 1

<any>/CID -> ivr

DID/<any> -> ringgroup 2

The ordering is indeterminate, because all patterns are stored in a single context
and asterisk is forced to choose. My biggest gripe with this is that asterisk
will always prioritize 'DID/<any>' over '<any>/CID' when the caller (CID) calls
the particular DID.

The ordering would require that the dial plan is generated differently. Each 'stage'
would be one or more patterns (assuming they are all any/CID, or DID/any, just not
a mixture) with a 's,1,Goto(inbound-routing-level-<N+1>)' at the top.

Asterisk would then attempt a match at level 1, when it fails, 's' will take it to
level 2, which if it fails, would take it to level 3..

Final 's' would either be the 'any/any' match, or standard route failure handling.

The ADMIN would then have the ability to decide if '<any>/CID' overrode 'DID/<any>'
on a per-DID/ per-CID basis simply by prioritizing.

Note that while '<any>/<any>' MUST by definition be at the end, allow it to be
prioritized like any other.

Add 'disable' flag to individual inbound routes to prevent dialplan generation.