feat: Introduce concept of dynamic relationships

[afonsobspinto]

Closes https://metacell.atlassian.net/browse/SCKAN-426

• Add new Relationship (custom property), Triple (options for each custom property), ConnectivityStatementTriple (option selected for a relationship in a connectivity statement); + migrations

• Updates admin page to allow Relationship and Triple creations (+ also a simple inline for the ConnectivityStatementTriple)

• Adds new ConnectivityStatementTriple viewset to support the webapp needs (see https://metacell.atlassian.net/browse/SCKAN-426?focusedCommentId=20071 thread for details)

• Adds inject_dynamic_relationship_schema function to inject the created relationships into the json schema endpoint.

• Updates export to add a new row for each statement_triples that exists in the connectivity statement to be exported
  (example https://docs.google.com/spreadsheets/d/1s9mynK-XYHZAjWu95_bO9gFTI1hctylDHoK4BOqSbHo/edit?usp=sharing)

Misc:

• Reposition CSRF_TRUSTED_ORIGINS so they are not overwritten by cloudharness django settings
• Make frontend proxy redirect to 127.0.0.1 opposed to localhost
• Add port-forward.sh ch's utility for the unlikely need of wanting to run connected to a remote cluster

[ddelpiano]

overall looks pretty good, great job to both @Salam-Dalloul and @afonsobspinto.

[ddelpiano]

@afonsobspinto one more comment, triples in combination of name+uri+relationship should be unique, I can see from the code that you can create the same triple per relationship as many times as you want.

[afonsobspinto]

@afonsobspinto one more comment, triples in combination of name+uri+relationship should be unique, I can see from the code that you can create the same triple per relationship as many times as you want.

#483

[ddelpiano]

lgtm