Limit instance type repertoire by capabilities

As of BBB plugin 2.24 any editingteacher can add ANY of the three BBB  instance types, that  may be:

• BIGBLUEBUTTONBN_TYPE_ALL
• BIGBLUEBUTTONBN_TYPE_ROOM_ONLY
• BIGBLUEBUTTONBN_TYPE_RECORDING_ONLY

However, there may be many scenarios in which some users must do recordings in some courses, but other user may only consume recordings done elsewhere, or may only add live session rooms WITHOUT recording session capability.

For instance, only a subset of techers create videos in some courses. Othet teacheres are allowed meet with students in live sessions but not to make recordings consuming disk space. 

In addition, recordingsBN is deprecated, but adding an instance on BBB as is now will allow live sessions, in addition to display previously recorded sessions.

I have added two capabilities in bd/access.php

'mod/bigbluebuttonbn:record' to allow/prevent to be able to record a session. It capability is false the teacher can create a room session, but cannot meke a recording (recording icons is NOT in the UI)

'mod/bigbluebuttonbn:room' to allow/prevent to be able to create room session.

If the teacher do not have any of the to, can only import pre.recorded sessions.

This is coupled to a re-definition of function

bigbluebuttonbn_get_instance_type_profiles($context = null)

to allow the building of 'instanceTypeProfiles array depending on user capabilities.