Allow saving the session (searches + expanded objects)

[mayhemer]

I am not happy with sharing finding (aka objects) through the URI. I also don't intend to remove it as it is somewhat useful - e.g. when you are diagnosing a single simple test failure, you just reload and see the same set of results.

What I want is to be able to add more data (like a line number to scroll to, or even highlight data + any manually added lines) which would simply produce too long URLs.

As we have full support for zip files now (even loaded from a URL!) we can add a 'logan.json' file with whatever data we wish.

There would be a button "save this session" to get that json file and add to the zip file t share.