Adds HTML title elements to templates that extend either `base.html`,
`portico.html` or `portico_signup.html`, and that are not website
portico landing pages that will use the `PAGE_TITLE` variable to set
the HTML title element (see following commit in series).
Also, updates some templates for missing translation tags.
As a general rule, we want the title element (and page content)
translated. Exceptions that are updated in this commit are templates
used in the development environment, analytics templates that are used
by staff and templates related to Zephyr.
This adds a web flow and management command for reactivating a Zulip
organization, with confirmation from one of the organization
administrators.
Further work is needed to make the emails nicer (ideally, we'd send
one email with all the admins on the `To` line, but the `send_email`
library doesn't support that).
Fixes#10783.
With significant tweaks to the email text by tabbott.
Lauryn Menard
Raymond Akornor