ui: refine visible URLs

[tiborsimko]

We can take advantage of the Live-Logs sprint and besides adding new endpoints offering live log streaming functionality, we can rethink the naming of all the visible endpoints.

For example, we are using currently /details/<id> but it would be more appropriate to call it /workflow/<id>.

For example, we might have a new URL for all the notebooks (interactive sessions) that the user has opened, strengthening even more the workflow vs notebook dichotomy, which could be represented in the URL.

We can therefore do:

• make a list of all active URIs;
• decide upon possibly renaming some, e.g. /details/<id> to /workflow/<id>;
• keep old names as aliases/redirects so that old URLs would work.