refactor zcl_abapgit_default_auth_info

[larshp]

refactor zcl_abapgit_default_auth_info, it is part of core abapGit no need to have it implemented twice

[mfsap]

zcl_abapgit_default_auth_info is currently not part of core abapGit. Either we bring it to core or we enhance zcl_abapgit_login_manager.

[larshp]

which enhancements are needed in zcl_abapgit_login_manager ?

[mfsap]

To avoid having several classes for credentials, it would be nice having one single class (zcl_abapgit_login_manager). It should "store" username/pw for a given repository as long as the session is alive.
The current implementation have a setter for username/pw. It would be perfect if it gets a getter method for username/pw as well.

[mfsap]

Then we can eliminate zcl_abagit_default_auth_info and use the login manager as substitude.