Adds a front end for:
https://github.com/alphagov/notifications-api/pull/2417
> Sometimes we have to make a few services for what really is one
> service, for example GOV.UK Pay and GOV.UK Pay Direct Debit. We also
> have our own test services which aren’t included in the count of live
> services. We currently count these as one service by not including
> them in the beta partners spreadsheet.
Most of the existing platform admin buttons on the service settings
page used to issue GET requests to switch service settings. This
means they weren't protected by CSRF. On top of that as our number
of service permissions increases over time a lot of buttons on the
page made it hard to work with.
To fix these issues we replace most of the buttons with rows in the
platform admin settings table. Each setting has a 'Change' link that
leads to a page with an On/Off switch form.
This removes "research mode" switch completely since we're planning
to deprecate it in the future and we don't expect to switch any new
services into research mode at the moment.
Most service permissions are now handled by a shared endpoint that
is parameterized with the permission name. Some permissions that
require some additional logic before they can be toggled (like document
upload, which requires setting a contact address) have separate
initial endpoints that redirect to `set_service_permission`.
"Archive", "Suspend" and "Resume" actions are kept as buttons since
they display a confirmation banner (which is a CSRF-protected form)
and they're not easily represented as an On/Off switch.
