Add datacatalog client

[tnsetting]

This PR adds a datacatalog client in flyteidl which could be used by flyte propeller and flyteCTL. As discussed with @kumare3 previously we will not register the config section in this PR because of compatibility issue with current config file in propeller. When all users have added the config section we will register the config in other PR.

Type

• [ ] Bug Fix
• [x] Feature
• [ ] Plugin

Are all requirements met?

• [ ] Code completed
• [ ] Smoke tested
• [ ] Unit tests added
• [ ] Code documentation added
• [ ] Any pending items have an associated Issue

Complete description

How did you fix the bug, make the feature etc. Link to any design docs etc

Tracking Issue

https://github.com/flyteorg/flyte/issues/839

Follow-up issue

NA OR https://github.com/lyft/flyte/issues/

[tnsetting]

@kumare3 PTAL. Thanks

[kumare3]

lgtm!

[tnsetting]

@kumare3 Please take a look

[tnsetting]

@kumare3 Could take another look for the PR?

[kumare3]

@EngHabu / @pmahindrakar-oss lets get the final review in and merge this change. Sorry for the delay @tnsetting