config: pass 'repo' directly to 'config_with_options()'

config: pass 'repo' directly to 'config_with_options()'

Add a 'struct repository' argument to 'config_with_options()' and remove the
'repo' field from 'struct git_config_source'.

A 'struct repository' instance was originally added to the config source in
e3e8bf046e9 (submodule-config: pass repo upon blob config read, 2021-08-16)
to improve how submodule blob config content was accessed. At the time, this
was the only use for a 'repository' instance, so it was naturally added only
where it was needed: to 'struct git_config_source'. However, in upcoming
patches, 'config_with_options()' will need the repository instance to access
extension information (regardless of whether a 'config_source' exists). To
make the 'struct repository' instance more easily accessible, move it into
the function's arguments.

Update all callers of 'config_with_options()' to pass the appropriate 'repo'
value:

* in 'builtin/config.c', use 'the_repository'
* in 'submodule--config.c', use the 'repo' arg in 'config_from_gitmodules()'
* in 'read_[very_]early_config()' & 'read_protected_config()', set 'repo' to
  NULL (repository instances aren't available there)
* in 'populate_remote_urls()', use the repo instance that has been added to
  the 'struct config_include_data'
* in 'repo_read_config()', use the given 'repo' arg

Finally, note that this patch eliminates the fallback to 'the_repository'
that previously existed for the 'config_source' repo instance if it was
NULL. The fallback is no longer necessary, as the 'repo' is set explicitly
in all cases where it is needed.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>