[telemetry] Add uid, org_id, and nix build event

[mikeland73]

Summary

This PR improves segment logging by:

• Adding orgID if user is logged in.
• Using userID if user is logged in.
• Removing anonymousID if userID is non zero. (Segment will remove userID if we pass an anonymousID)
• Add new event to track nix build

This allows us to:

• Use orgID to segment data, potentially allowing individual orgs to export/use their own data as needed.
• Track logged in users.
• Track which packages are slow to build.

Private Notes:

• We still respect DO_NOT_TRACK even if user is logged in.
• userID and orgID data is only sent if user is logged in.

cc: @Lagoja

How was it tested?

Logged to development segment/amplitude, built a quick table showing nix average build times:

[gcurtis]

Is there a way to get the current username without refreshing the token? I think that would also let us remove the context from the telemetry functions, which should probably still run even if the context is cancelled (to report things like timeouts).

[gcurtis]

Is there a way to never refresh the token here and in orgID?

[mikeland73]

yeah, our auth library has a GetSessions which returns refreshableTokenSource which have a Peek() function. I'll switch to that.