Collect should provide trunkVersion and branchId to servers

[seadowg]

Blocked by #6267

So that servers are able to deal with conflicts from multiple clients performing offline updates, Collect should provide trunkVersion and branchId as part of entity submissions.

Acceptance

Using XForms that include branchId as described in the new spec, the submission resulting from each of these actions satisfy the conditions in each of these scenarios:

• Updating a locally created entity
  • New branchId (UUID)
  • trunkVersion is blank
  • baseVersion is the updated entity's version (which will be 1)
• Updating an entity in the entity list (an "online" one)
  • New branchId (UUID)
  • trunkVersion is entity is the updated entity's version
  • baseVersion is entity is the updated entity's version
• Updating a locally updated entity
  • Same branchId as the last update submission for this entity
  • Same trunkVersion as the last update submission for this entity
  • baseVersion is entity is the updated entity's version

Additionally, XForms that do not behave as the spec describes and set baseVersion, branchId or trunkVersion to unexpected values should not affect Collect. For example, if a form always sets baseVersion to "5" instead of to the provided __version, Collect would still increment __version in its local representation instead of always ending up with "6".