Create Use-of-Password-Grant-Type.bcheck

[LabMC]

• Context: The Use-of-Password-Grant-Type file is used to detect for usage of the password grant_type in OAuth within GET & POST HTTP requests' HTTP request bodies.
• I have additionally added a /OAuth folder within the /other root folder.

BCheck Contributions

• [X] BCheck compiles and executes as expected
• [X] BCheck contains appropriate metadata (name, version, author, description and appropriate tags)
• [X] Only .bcheck files have been added or modified
• [X] BCheck is in the appropriate folder
• [X] PR contains single or limited number of BChecks (Multiple PRs are preferred)
• [X] BCheck attempts to minimize false positives