Offline entities

[seadowg]

Release blockers (prioritised):

• [x] #6029
• [x] #6031
• [x] #6011
• [ ] #6229
• [ ] #6245
• [ ] #6128
• [ ] #6012
• [ ] #5623
• [ ] #6231
• [ ] #6232
• [x] There's most likely forms that don't meet the spec that can be filled (create without label for instance) or will cause the app to crash

To improve:

• [ ] No log of changes to entities (should be available outside)
• [x] Datasets are downloaded and stored for every form
• [x] Online entities are not shown in browser
• [x] Form loading takes longer for entity follow up forms (because of building combined instance) than normal secondary instance forms
  • The is quite severe due to n^2 lookups required for deduplicating
• [ ] #6030
• [ ] A form with a secondary instance matching an entity list in the same project will get the entity list instead of the secondary instance