Abtract Class is missing for OAuthReqMessageContext

[inthirakumaaran]

Description:
Although OAuthTokenReqMessageContext and OAuthAuthzReqMessageContext classes have many common attributes and methods, there are written separately. It is better to create an abstract class and then extend these classes from that.

Suggested Labels:
enhancement

Suggested Assignees:
@mefarazath @JKAUSHALYA

Affected Product Version:
5.4

OS, DB, other environment details and versions:
N/A

Steps to reproduce:
N/A

Related Issues:

N/A