Deploy should report conflicts before replication

Problem

Currently, Deploy will push conflicts between Workspaces without notifying the user. This could mean data loss, at least as far as the user is concerned.

Longer explanation about data loss: the data isn't lost, it's still in the database, it's just there's no way to resolve conflicts at present. So, for example, say Workspace B has its upstream set to Workspace A and let's say they both have a node entity titled "Rabbit". Let's say A has revision 1 of this entity and B has revision 2, when A is deployed to B, there will be a conflict. Both revisions will be stored, however, a revision 3 will be created that is the arbitrary winner of these revisions. Let's say the winner was revision 2, but the user wanted revision 1, they currently have no way to get back to revision 1.

Longer explanation about replication: When a deployment is created, it calls the "replicate" method on the replicator. The replicator will do two things: (A) update the current Workspace with data from its upstream, and then (B) push changes to that upstream. Implicit in this is that conflicts are not discovered until step A, which means the caller of replicate has no way to know if conflicts are being pushed upstream.

Proposed Solution

The Workspace module as of #2791789: Workspace should report conflicts before replication has solved this problem for this module.

That ticket adds a flag that tells the replicator to abort if conflicts are discovered during replication. This is done through setting a static variable "workspace_is_aborted_on_conflicts". Deploy should be updated to set this value to TRUE by default to prevent the user from unknowingly pushing conflicts upstream. Additionally, a user input should be created on any form that triggers a deployment to allow the user to set this variable and push those conflicts upstream if they wish.