Visualization export/restore v1.0

[Kartones]

Subset of #5578

As a user I want a way to recover user visualization critical data with a rake or similar method

Best effort rebuilding

• layers
• overlays
• viz and its info/metadata

Notes:

• no user db data will be recovered
• other metadata and associated models won't be recovered, so
  • some will get default values (e.g. permissions)
  • some won't be available (e.g. synchronizations)

Tasks:

• Rakes to manually trigger save/restore
• DB table for backups
• Plug automatic save upon saving
• DB-based store & recovery
• Deletion of DB data after recovery (or manual call)
• Logic to save/restore full visualization data
  • Pending: Testing other basemap layer options.
• Rake to purge old data from backups DB table
• Feature-flag control the storing or not of backups
• Automated test to at least verify some basic skeleton is reimported properly

V1.1 Tasks:

• Logic to support partial restore of visualization data ??? (e.g. only a missing data layer). by layer name maybe? (table_name check as probably can be non-unique)

Branches:

5710-new-table-rake

5710-viz-backup-restore