Add routing and urls for specific map views

[Rikuoja]

Parameters to include:

• map bounds (better than zoom + center, if we have different sized clients?). Bounds cannot be shared exactly tho, because the clients also have different shapes.
• selected item (requires implementing https://github.com/GispoCoding/tarmo/issues/171 first)

This way, user can

• share links to specific areas on the map or specific items
• press the back button to get back to the previous area, instead of losing the whole app. "Peruuttaminen edelliseen sivuun tai kohtaan kartalla oli hankalaa, ohjelma heitti alkuun."

[Rikuoja]

Duplicate of #148