NEW: Updating out of date URLs in the framework source code and docs

Ran the BrokenScriptsURL dev task from the check-source-urls module 

https://github.com/silverstripe-rebelalliance/check-source-urls

and found the following out of date and invalid URLS (the changelogs directory was ignored).

It did find a lot more but as they were mainly in the thirdparty directory I ignored them.