Bluetooth: Mesh: Add Opcodes Aggregator models to shell

- Add entry for client and server in composition data.
- Add Client commands to aggregate and send messages.

MESH/SR/AGG/BV-02-C requires more key slots.

Co-authored-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>
Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>