Adds the component which receives the messages from client and a module which enabled on a virtual host will start advertising the component. When clients discover the component they will send message to the component with the name of the room where the dominant speaker event happen.

The original presence stanza generation code for a poltergeist
has been re-factored and simplified a bit. Every time a
poltergeist presence is updated we first check that the poltergeist
still exists.

* Adds an option to disable features based on token data.

Reverts changes from b84e910086, removes disableDesktopSharing option and an interface_config option.

* Disable recording button based on token features data.

Hide recording if local participant isGuest and roles based on token.
When enableUserRolesBasedOnToken is enabled we were not hiding the record button for guests.

* Adds filtering of jibri iqs and rayo based on features.

Moves feature checking in separate utility function.
Renames utility method.

* Adds a footer text when outbound-call is not feature enabled.

* Fixes comments.

Previously a new call id was generated for INVITE and CANCEL.
Now the id generated during the initial INVITE will be used for
corresponding CANCEL events. Also, adding the ability to
trigger a call cancel via the poltergeist update api.

The current poltergeist http api immediately returns
and does not wait for async work in the handler to finish. This
mostly occurs when a public asap key needs to be fetched due
to a cache miss. The fix implements the strategy described at
https://prosody.im/doc/developers/http.html

This should allow us to have a consistent convention and assist
with client translation of status strings.

When combined with mod_muc_poltergeist mod_muc_call allows
for enabling call features using a proper ext_events.lib.lua
implementation. By default when the module is configured only
stub implementations are used for ext_events.lib.lua as these
are unique between deployments.

* add a prosody module to insert identity information (when available) into
presence

prosody will check for jitsi_meet_context_user and
jitsi_meet_context_group in the session and, if they are present, insert
them into presence (we do this in prosody so they cannot be spoofed).

* remove unused 'presence' variable

* refactor to modify presence message in place

* make object member access consistent

* make the group information optional

This was broken with commit c1fb1a7def, which splits the result in order to print the error reason and in case of error was not returning the error and the message to prosody internals.

Adds some debug messages when token verification fails for some reason.

fixes handling of keyserver ASAP validation of tokens
wraps room and room-size APIs

set up async context for all poltergeist calls
utils lib now has async wrapper for event handlers

If we do not reuse previous presences we lose avatar and name and people joining after the poltergeist creation will not be updated with those values.

Adds http method to remove poltergeists. Adds configurable timeout after which poltergeists automatically are removed from the room.

Thanks to Matthew Wild for the initial help of creating these.
Module with REST interface to create poltergeist participants and change their statuses.
When user with same id joins the room, the poltergeist is removed.  We also make sure that that user uses same username when authenticates. This way we are sure that user will join the room with the same nick as the poltergeist.

This is a hook to override the username that will be used when authenticating token users (which are using anonymous login with auto-generated username).

* added checks for audience and issuer values
default audience and issuer checks to validate only appId
added missing documentation lines from the previous PR for context_user and context_group session values

* support for accepting any audience
option set to accept any audience by default

stick user and group from token context into session if available