Suggestion for some extra links in UI

[ColemanTom]

I was looking at the UI and I thought that clicking on the logo in the top left should direct you somewhere.

I thought that perhaps it shoudl take you to the "home" of the UI, e.g. https://hostname/user/my_usernamecylc/#/

Secondly, I thought it would be nice to have easy to access links from the UI to documentation. I know you can via the Cylc Hub, but I'm probably more meaning the "UI quickstart documentation" from the Hub. I think it would be useful to be able to see what all the symbols and colours mean without going back to the hub. Be able to view it next to the tree/graph type display - like you can have two views next to each other, being able to have one of those views be the UI Quickstart documentation would be useful for people who use the UI intermittently.