Remove leading/trailing whitespace from credit parts

[cpeel]

Ensure that all components used to build the credits field do not have leading or trailing whitespace. This could come from a user's real name field or "other" value, scanner credit, or extra credit.

Note we don't have to do this for usernames as leading and trailing whitespace characters are not valid in usernames.

Fixes #1570

Sandbox: https://www.pgdp.org/~cpeel/c.branch/trim-credit-components/

[srjfoo]

😁 -- this was challenging to test. What I wound up having to do ultimately was register a new TEST user with spaces trailing the real_name field. Updating your profile, you can't add trailing spaces to the real name, though you can to the credit name.

What turned out to be the challenge was that, as far as I could tell, the credit name field was already being trimmed. And the PPer field was already being trimmed. What wasn't being trimmed was the PM field.

To save others the trouble, compare the main test server with the sandbox

[windymilla]

Thanks - that looks great!