feat: [AAP-47707] allow credentials to link to external SMS

[kaiokmo]

https://issues.redhat.com/browse/AAP-47707

Based on eda-server PR 1361[1], now EDA allows credentials to link to external Secret Management Systems (SMS), like Hashicorp Vault and others.

To comply with the back-end functionality, this PR adds 2 new modules to the collection:

• credential_input_source
• credential_input_source_info

We also implement the "test" functionality to credential and credential_type, which essentially adds support to reach the test credential endpoints to check if a credential is working as expected before actually creating the credential.

[1] ansible/eda-server#1361

[hsong-rh]

@kaiokmo I have two questions:

1. We have credential and credential_type modules already. Should we add the test functions there, instead of creating new modules credential_test and credential_type_test?
2. We also need to update the main.yml of credential and credential_type for the test function, right? Like what you added for credential_input_source?

[kaiokmo]

@kaiokmo I have two questions:

1. We have `credential` and `credential_type` modules already. Should we add the `test` functions there, instead of creating new modules `credential_test` and `credential_type_test`?

2. We also need to update the main.yml of `credential` and `credential_type` for the `test` function, right? Like what you added for `credential_input_source`?

@hsong-rh that's a great point. I think it makes sense to extract the functionality of credential_test and credential_type_test into the already existing credential and credential_type modules. I will change the modules accordingly and also the integration tests.