Remove default identifier on api/view

Instead of defaulting to a specific id/sha1 on endpoints, display informational explanation on what the endpoint is all about. Then give some possible existing links to default one.

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Migrated from T291 (view on Phabricator)

added Web app priority:Normal labels

This has been partially done during the completion of !7 (closed). The browsing and API endpoints now have no default parameters, but we have no replacement solution for providing user-friendly documentation for the endpoints. The most interesting lead for now would be a custom documentation decorator to wrap the route functions in order to provide default arguments //without// hard-coding default arguments to the routes.

The use-case I have in mind is that a user wanting documentation for the API will browse to, for example, /api/1/revision/ to get information about what parameters they should supply to the endpoint. Currently, browsing to that URL will break the app and return a werkzeug debug page (in dev mode).

The difficulty is determining //how// to provide documentation to fit the routes, particularly if there are multiple routes that have the same base (for example, /api/1/revision/<sha1>/ is //very// different from /api/1/revision/<origin>/<branch>/<timestamp>/. Perhaps creating documentation in a less programmatic way, or providing a more global overview, would be in order.

added priority:Low label and removed priority:Normal label

Closed due to #431 (closed) overriding this task.

assigned to @jbertran

closed