SOC-3698 Space creation failed due to JCRItemExistsException at ADD PROPERTY

Problem analysis:
* When creating an activity reference in multi-thread mode, each thread tries to create a new year/month/day reference.
  That raises the ItemExistsException.
* When using space injectors, the space number variable gets wrong value of user number from REST.
  The space injection then failed when these values are not the same.

Fix description:
* Check if the node for year/month/day reference exists before creating a new node.
* In Space injector, get the number of space from the input value.
Merge commit '9ef097b279f4f31440b3a69f272648cbb513398f' into HEAD