Improve settings/account page

[chrislo]

niceberg suggested some changes to the settings/account page in his redesigns of jam.coop. In particular bringing the artist/album edit pages into the users profile area rather than having a link from the release/artist page. The improved UI and introduciton of tabs to access different sections should make it easier to find a place for, for example, Stripe Connect settings (#90).

The following screen grab from Figma is representative of the change I want to make, we're not implementing everything in these designs yet, so will have to find a middle ground between what we have now and this.