Allow DFID User to select multiple fund values

This commit changes the value_of_fund input to be a multi-select. We
don't need to change this anywhere else as the rest of the Finder stack
always treats metadata as arrays.
Cleanup work on new observers

Change the naming of methods within the observers to match what's used
already for CMA cases and IDF's.

Fix a (supposed) bug where we didn't notify panopticon on update of an
aaib report.

Remove legacy TODO.
Fix republishing script

All observer registries are now format-specific. There is no generic
`observers` value in the wiring any more.
Merge pull request #206 from alphagov/fix-republish-script

Fix republishing script
Merge pull request #205 from alphagov/extract-all-observers-to-registries-cleanup

Cleanup work on new observers
Merge pull request #201 from alphagov/allow-dfid-user-to-select-multiple-funds

Allow DFID User to select multiple fund values
Export to rummager whenever a manual is published

When a manual is published, tell rummager about both the manual and its
sections.

Rummager then adds them to the elasticsearch index, so that we can make
them appear in search results.
Merge pull request #207 from alphagov/notify-rummager-on-manual-publication

Export to rummager whenever a manual is published
Adding sidekiq
Renaming ManualServiceRegistry to Organisational

We renamed this to create another ManualServiceRegistry which isn't
scoped by the User's Organisation.
Introduce a Publishing Workers Layer

This commit adds a workers registry which allows us to call a worker
from the controller which in turn can call the services and perform them
asynchronously.

Also allowing tests to run as normal when creating  background workers.