Multiple "spaces" - ability to switch between multiple accounts

[santomet]

The most important feature I am looking for in a 3rd-party WA client is the ability to run multiple accounts simultaneously with fast switching between them i.e. in a sidebar.

I would imagine multiple local storage + cookie "spaces" may allow for that

This is related to issues #373 and #318 but instead of the need for two instances, I would like to have everything in one window.