Feature index overlay bug

[prushforth]

Supporting PR in mapml-extension

• [x] Make map the focus after following a link e.g. on this map
• [x] Make map the focus after reload() etc.
• [x] Verify that checking/unchecking layers works for feature index behaviour
• [x] Add test for post-geolocation activation, deactivation
• [x] Add test for post-link activation
• [x] Make output responsive (fit between lower controls without overlap)

[prushforth]

@malvoz there are significant changes in this PR, would be great if you would have a look. Also: should this be a control?

[AliyanH]

moved to #873