Start the filter plan
Start the filter plan

Details:
  * add a new plan: `filter_plan`
  * add a new target: `census_tracts`
  * add a new target: `filters_tract`
  * add a new target: `filters` (all filters)

Notes:
  * this is a WIP

tiernanmartin/home-and-hope,tiernanmartin/home-and-hope,tiernanmartin/home-and-hope