kamailio: Add support for Media Relay Sets and Application Server Sets

[cruzccl]

Type Of Change

• Small bug fix
• New feature or enhancement
• Breaking change

Checklist:

• Commits are named and have tag following commit rules
• Commits are split per component (schema, portal/platform, kamusers, agis, ..)
• Changes have been tested locally
• Fixes an existing issue (Fixes #XXXX)
• Upport from existing Pull request #XXXX

Description

ApplicationServers now can be grouped into sets and assigned to desired clients.

Additional information

Mediarelaysets can also be grouped into sets (it was possible before too) and this PR adds some necessary rework here.