This commit adds a button to the `CallActionList` to signal to the
other participants of the call that one is raising a hand.
This will add a hand icon to the `CallParticipantCard` of the people
with a raised hand and send a notification that is displayed in the
`Call` view (only when in discuss, not in chat windows).
task-3229507
closesodoo/odoo#116658
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>