refactor: Move auth extractors into authentication module

[tpoliaw]

Splitting up the auth extractor method allows other extractors to access the raw token as well as easy access to the validated and decoded access token.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.63%. Comparing base (ab2ebc6) to head (3b5b8a2).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1547      +/-   ##
==========================================
+ Coverage   95.61%   95.63%   +0.01%     
==========================================
  Files          43       43              
  Lines        3214     3228      +14     
==========================================
+ Hits         3073     3087      +14     
  Misses        141      141              

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[ZohebShaikh]

Generally I think why write extra code when it is already been written by someone else ?

[ZohebShaikh]

This is a copy of this

    authorization = request.headers.get("Authorization")
    scheme, param = get_authorization_scheme_param(authorization)
    if not authorization or scheme.lower() != "bearer":
        if self.auto_error:
            raise self.make_not_authenticated_error()
        else:
            return None  # pragma: nocover
    return param

Why not use the function already in fastAPI ?

After this PR you only use it at 1 more place.
A better thing to do would be to create oauth_scheme in main

oauth_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="",
    tokenUrl="",
    refreshUrl=None,
)

and do depend(oauth_scheme) to get the unchecked_access_token

To a certain extend I get that you want authN related stuff to be in the authentication.py file