Clean up [identity-feature-enable] options for old releases

Project tags API and application credentials API are default features
since Queens and we can now assume these features are available when
identity v3 API is available. Becuase queens and older releases are no
longer supported by tempest, we can drop the options to enable tests
for these features.

Also, access rules for application credentials has been a default
feature since train so we can also assume this feature is available,
because train and older releases are no longer supported.

Change-Id: I138ac02f61c5a0a22ce0d5ad2d600a09166a4764
4 files changed