accessibility: buttons should use aria-pressed

[derekeder]

From #45 (comment)

[derekeder]

from @vkoves:

We want aria-pressed="true" to be added to the button whenever the active class is applied.

This needs to be done in javascript, so a convenient way to do it would be to create a toggleActive() function that both sets the class for an element and then adds the aria-pressed value too.

We would do this everywhere the active class was being added / removed.
https://github.com/chihacknight/il-solar-map/blob/main/js/map.js#L295

[derekeder]

closed via #62