Refactors search mechanics: part 2

[psdcode]

Part 2 of the refactor and general fixes of most of the bugs and issues present in the old search interface:

Note, this PR contains changes from the previous PR https://github.com/ajah/sks-interface/pull/50, either merge that first before this one, or close it and just merge this one.

In this PR:

• Everything already described in https://github.com/ajah/sks-interface/pull/50
• readds support for location region filter
  • adds missing territories (eg, Yukon, Nunavut, NT)
• add support for multiple (previously entered) keywords, as indicated by little tiles above search box
  • it is now possible to add and remove tile keywords
  • adds limit of max 5 keywords. when it is reached input field is disabled. Each term can be a max of 30 chars each
• makes all api calls use api service
  • env variable allows to specify server address (can specify localhost if working on server locally)
• Replaces redundant extra back button component specific to Grants page by the single main back button component
• resolves https://github.com/ajah/sks-interface/issues/38 : can now delete last tile
• resolves https://github.com/ajah/sks-interface/issues/32 : left hand filters now update results automatically
• resolves https://github.com/ajah/sks-interface/issues/6 : multiple word search teerms now reside in one tile pill above the search box
• resolves https://github.com/ajah/sks-interface/issues/4 : results load automatically when change filter
• resolves https://github.com/ajah/sks-interface/issues/5
• resolves https://github.com/ajah/sks-interface/issues/1 : back button should return to results from which we arrived

Note: City filter will be reenabled in a subsequent PR dedicated to it as the UI for it requires a rebuild

[psdcode]

Found a small bug when checking the grants page at this URL: http://localhost:3000/activities/179493 Mind committing a fix?

Fixed!