Convert UUIDs to alphanumeric representation

Fixed B-179, which had a bunch of warnings due to a UUID object being used
instead of the alphanumerical representation is expects.

https://trello.com/c/0TVoguJf/292-b-179-recent-changes-on-flow-extra-is-borked-beyond-recognition

Change-Id: I45685bbc526acdc455568ee4668c442dcc549db3
Merge "Convert UUIDs to alphanumeric representation" into frontend-rewrite