Followup to b53449eac9,
it was too easy to add broken routes which would break
configuration for the whole site, so now we validate ember
routes on save.
Followup to b53449eac9, we cannot
generate the links to plugin admin pages in this way because it
depends on which plugins are installed; we would need to somehow
do it at runtime. Leaving it out for now, for people who need to
find these admin routes the Ember Inspector extension for Chrome
can be used in the meantime.
NOTE: Most of this is experimental and will be removed at a later
time, which is why things like translations have not been added.
The new /admin-revamp UI uses a sidebar for admin nav. This initial
step adds a script to generate a map of all the current admin nav
into a format the sidebar to read. Then, people can experiment
with different changes to this structure.
The structure can then be edited from `/admin-revamp/config/sidebar-experiment`,
and it is saved to local storage so people can visually experiment with different ways
of showing the admin sidebar links.
