Nunjucks: move transition.context out of the transition variable

Description

Right now, the execution context (of the post-function) is accessible through:

This is where we store certain things, such as the newIssueKey. We should move that to a top-level context global variable, next to transition instead of inside it.
Of course, we need to keep the context property inside the transition variable as well, for backward compatibility.

This requires updating the Nunjucks Globals help tab

Environment

None

Customer Info

None
Fixed

Assignee

Unassigned

Reporter

David Fischer [Innovalog]

Labels

None

Internal Complexity

Unknown

Internal Value

Unknown

Requires documentation

Requires documentation

Impact

None

Fix versions

Priority

Major
Configure