[sr-dev] RFC: deprecating add_contact_alias()

Both add_contact_alias() and set_contact_alias() are adding the following new param ";alias=ip~port~transport" to the Contact header. There are some subtle differences between the two: set_contact_alias() makes the contact URI is immediately visible to other modules. Recently, Daniel made a fix for set_contact_alias() to work with presence modules (just like fix_nated_contact() does). Since both add_contact_alias() and set_contact_alias() are doing similar things, but add_contact_alias() has some limitations, I would propose to deprecate add_contact_alias() in favour of set_contact_alias().