This commit updates restrict-permissions-of-new-members.md
to add "inviting users to organization" in the list of actions
that can be restricted for new members.
We also fix the subsection of waiting_period_threshold to be
"Joining the organization".
This commit includes a new `stream_post_policy` setting,
by replacing the `is_announcement_only` field from the Stream model,
which is done by mirroring the structure of the existing
`create_stream_policy`.
It includes the necessary schema and database migrations to migrate
the is_announcement_only boolean field to stream_post_policy,
a smallPositiveInteger field similar to many other settings.
This change is done to allow organization administrators to restrict
new members from creating and posting to a stream. However, this does
not affect admins who are new members.
With many tweaks by tabbott to documentation under /help, etc.
Fixes#13616.
sahil839
Tim Abbott
Ryan Rehman
Rishi Gupta