Increase data stored in the url

[manthey]

We store some data in the url (e.g., image position, selected analysis task). It would be good to add frame selection, viewed annotations, task options that aren't the default, etc. so that a url could better recreate the state of the viewer.

There could be enough options that this would exceed the sensible browser url size (although this varies by browser, 2k is the same limit). Perhaps we should save this state to a database collection and have a reference to it (maybe when a sharable link is asked for?).