feat: Add clerk_organization & clerk_organization_id helpers

[agis]

This fetches the organization ID of the currently authenticated session, if any. Otherwise it returns nil.

[agis]

What about clerk_organization?

Thought about that, but it would be inconsistent with the other helpers. We currently have:

• clerk_user which returns a User object
• clerk_user_id which returns the User's ID

Following that same convention, it made sense for it to be suffixed with _id since it returns an ID.

Then, I chose org over organization for convenience/brevity. Do you think we should change it to clerk_organization_id?

[SokratisVidros]

That's right. I am suggesting to have both, clerk_organization should return the full clerk_organization object.

[agis]

Overhauled this to introduce two new helpers:

• clerk_organization does a BAPI call to fetch the organization object, if any
• clerk_organization_id returns the org ID (if any) by merely peeking at the session token

@SokratisVidros PTAL.