groups: Add module to manage devices groups

This will help to organize groups between different profiles.
This module is responsible for assiging group id and keeps a
list of groups.

Bug: 150670922
Tag: #feature
Test: atest --host bluetooth_groups_test
Sponsor: jpawlowski@
Merged-In: I778b4432ef024c308727ea68094c861142de3fdd
Change-Id: I778b4432ef024c308727ea68094c861142de3fdd