Let content packs change map properties, so you don't need specialised (and sometimes infrequently maintained) map frameworks for basic changes. Continued from #409.

Split from #409:

• Proposed usage to change a map property:

  {
     "Action": "EditLocation",
     "Target": "Town",
     "MapProperties": {
        "Warp": "10 10 Farm 0 0"
     }
  }

  Replacing a map property entirely isn't ideal in some cases (e.g. multiple mods may need to add warps to a location). This should also support appending/prepending using a special 'previousValue' token (trimmed if needed):

  {
     "Action": "EditLocation",
     "Target": "Town",
     "MapProperties": {
        "Warp": "{{previousValue}} 10 10 Farm 0 0"
     }
  }

  And possibly search/replace logic:

  {
     "Action": "EditLocation",
     "Target": "Town",
     "MapProperties": {
        "Warp": {
          "Search": "10 10 Farm 45 30",
          "Replace": "10 10 Farm 0 0" 
        }
     }
  }

• This could maybe support other location fields in future versions, like...

  {
     "Action": "EditLocation",
     "Target": "Town",
     "Fields": {
        "IsGreenhouse": true
     }
  }

Done in develop for the upcoming Content Patcher 1.10.

The {{PreviousValue}} token proposed above isn't currently supported, since it doesn't work with the current Content Patcher design (because the value can't be evaluated ahead of time).