This commit revamps the invite type section of the "Invite user" modal
to provide a more intuitive user experience. The section now includes a
radio button option with two choices: "Send an email" and "Generate an
invite link." The email input box is hidden when the "Generate an invite
link" option is selected.
Fixes#24692.
These files are not Jinja2 templates, so there's no reason that they needed
to be inside `templates/zerver`. Moving them to the top level reflects their
importance and also makes it feel nicer to work on editing the help center content,
without it being unnecessary buried deep in the codebase.
Alya Abbott
Ujjawal Modi
David Rosa
Akarsh Jain
Lauryn Menard