Move site selector from top bar to top controls (MultiSites)

[diosmosis]

A small start to #974

Add new top control for site selection instead of using the existing drop down in the top bar. This control will eventually be displayed in the WP back office.

Things to be taken into consideration:

• Users that are used to the top bar control may be confused when it is moved. We need to let them know that it moved.

[mattab]

Nice idea! Would it be possible to see a mockup of what it would look like roughly?

[diosmosis]

@mattab should look exactly like on premise Matomo:

[mattab]

When I look at MWP, there is no site selector, because I only have 1 WP site. Is this issue maybe only relevant when used in "Multisite" mode?

[diosmosis]

Yes only relevant for WP Multisite. Currently the site selection dropdown is in the top bar, but I want to move it to the normal site selector position.