[PACE-23] Determine strategy for overlapping transforms in GlobalTransforms / Data Policies #33

The global transforms that belong to various tags (or when combining a Data Policy's transforms with the transforms defined in the Global Transforms) can be overlapping / can collide. We should think of the strategy we want to apply in this situation. Multiple options:

1. First one wins (this is determined by the order in which the tags are returned by the processing platform / data catalog) -> possible leads to unexpected / unwanted policies.
2. Merge (how?)
3. Strict mode -> refuse to generate a bare policy with global transforms and let the end user first remove the overlap.

The UI will be very helpful here: showing whether the GlobalTransform is compatible with the Data Policy, and if not, what the conflicts are.

_{From SyncLinear.com | PACE-23}