Replace neighborhood data

[entrotech]

Fixes #2509
Replaced neighborhood boundary data with current data from https://geohub.lacity.org/datasets/neighborhood-council-boundaries-2018/explore.

This involved

• Downloading data from the above web site
• editing the GeoJSON file for import
• uploading to a neighborhood_load table
• nulling all FK references to neighborhood_id in stakeholder, stakeholder_best and stakeholder_log tables.
• truncating the existing neighborhood table
• adding and deleting columns in the nighborhood table to reflect current data from the source.
• inserting data from the neighborhood_load table to appropriate fields in the neighborhood table.
• re-mapping the nieghborhood_id columns in the stakeholder, stakeholder_best and stakeholder_log tables to the new neighborhood definitions.