Support authn-ldap

[szh]

Depends on #410, https://github.com/cyberark/conjur-api-python/pull/23

Desired Outcome

The conjur init command should support LDAP authentication. It should be possible to specify the authentication type using the -t or --authn-type option. The default value should be authn (same as current), and it should additionally support ldap. When using ldap, a --service-id option should be mandatory. If the --service-id option is specified, then --authn-type should default to ldap.

The CLI implementation should be straightforward. It needs to support the new CLI arguments in the init command, and it will need to pass them to the conjur-api-python library.

Create new and update existing unit and integration tests.

Implemented Changes

• Updated README.md to state that the project is at the Community certification level, reflecting the lack of adequate testing in this and the cyberark/conjur-api-python repository which it depends on.

Connected Issue/Story

Resolves #264, #324

CyberArk internal issue link: ONYX-20431

Definition of Done

• [x] conjur init supports --authn-type and --service-id parameters

Changelog

• [x] The CHANGELOG has been updated, or
• [ ] This PR does not include user-facing changes and doesn't require a CHANGELOG update

Test coverage

• [x] This PR includes new unit and integration tests to go with the code changes, or
• [ ] The changes in this PR do not require tests

Documentation

• [ ] Docs (e.g. READMEs) were updated in this PR
• [ ] A follow-up issue to update official docs has been filed here: [insert issue ID]()
• [x] This PR does not require updating any documentation

Behavior

• [ ] This PR changes product behavior and has been reviewed by a PO, or
• [x] These changes are part of a larger initiative that will be reviewed later, or
• [ ] No behavior was changed with this PR

Security

• [ ] Security architect has reviewed the changes in this PR,
• [x] These changes are part of a larger initiative with a separate security review, or
• [ ] There are no security aspects to these changes

[szh]

@jdumas I'd love to hear your input on this since you were the one behind #324. Does this solve your use case? Are you able to test this locally and see if it works for you?

[jdumas]

Sorry I'm not using Conjur much these days, so I won't be able to test this for a while :(