Sipmsg validate all contacts

[davidtrihy-genesys]

Summary
Extends sipmsg_validate with c flag set for validating Contact headers to multiple different requests

Details
In response to my testing of the fix outlined in this PR #3803 I found limitations of the sipmsg_validate function which only applied Contact validation to INVITE.

This extends validation to REGISTER|UPDATE|SUBSCRIBE|REFER - not taking into account what type of request it is eg. initial or in dialog, so with a REFER a dialog can be created from a REFER request according to https://www.rfc-editor.org/rfc/rfc3515#section-2 but an in dialog REFER does not honour the Contact header sent but this validation logic does not check that and it will fail, it is designed to be up to the script writer to do the in dialog check themselves.

Solution
New static function created to specifically check the Contact header which will take into account multiple different aspects of the SIP message.

Failure conditions

1. No Contact header
2. Contact header contains * as the body and one of these other conditions
   i. Is a SIP reply
   ii. is not a REGISTER request
   iii. is a REGISTER request but the Expires header is missing or it is set to a value greater than 0

New return code of -30 for when a * is the value but is invalid for the three types of conditions listed in 2.

Compatibility
Depending on how you have written your script and if the behaviour of your OpenSIPs deployment is relying implicitly on the Contact header not being checked for the new requests it could break scripts.

[bogdan-iancu]

The patch looks fine thank you.
If I may suggest a small simplifying of the code, to get rid of this repeating sequence of:

ret = ... ;
goto failed;

where there is just a return ret.
I would suggest simply doing an inline of return ...... ; instead of setting ret + goto. Also drop the failed label and do return SV_NO_ERROR; at the end.
Up to you if you want to do this change :)

[davidtrihy-genesys]

@bogdan-iancu I did the inline return, makes more sense so ready to merge whenever CI is good thanks

[bogdan-iancu]

Thank you @davidtrihy-genesys