Added new Event Type in AbstractRealmAuditLog STREAM_CREATED.
Since we finally create streams in create_stream_if_needed function
in zerver/lib/streams.py so logged realm_audit there.
Passed acting_user when create_stream_if_needed or ensure_stream
function is called.
Added tests in test_audit_log.
Refactored code in actions.py and streams.py to move stream related
functions into streams.py and remove the dependency on actions.py.
validate_sender_can_write_to_stream function in actions.py was renamed
to access_stream_for_send_message in streams.py.
This is a preparatory commit for using isort for sorting all of our
imports, merging changes to files where we can easily review the
changes as something we're happy with.
These are also files with relatively little active development, which
means we don't expect much merge conflict risk from these changes.
This library was absolutely essential as part of our Python 2->3
migration process, but all of its calls should be either no-ops or
encode/decode operations.
Note also that the library has been wrong since the incorrect
refactoring in 1f9244e060.
Fixes#10807.
Finishes the refactoring started in c1bbd8d. The goal of the refactoring is
to change the argument to get_realm from a Realm.domain to a
Realm.string_id. The steps were
* Add a new function, get_realm_by_string_id.
* Change all calls to get_realm to use get_realm_by_string_id instead.
* Remove get_realm.
* (This commit) Rename get_realm_by_string_id to get_realm.
Part of a larger migration to remove the Realm.domain field entirely.
* get_realm returns None if no matching realm is present, but
create_stream.py assumed it raises Realm.DoesNotExist.
* encoded/decode strings properly.
