Add couchbase plugin

[rishabh]

What does this PR do?

Add the couchbase integration.

Plugin Checklist

• Unit tests.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CircleCI jobs/workflows.
• Plugin is exported.

Additional Notes

Work in progress, I need to fix cbas (analytics) queries. View queries also don't work for some reason.

I'm using https://github.com/rishabh/server-sandbox/ as the test image.

[rishabh]

Tests are failing because the full-text search service availability isn't sent to the SDK when it first connects to the cluster. This appears to be a bug in couchbase since you actually can execute a search query just fine through the web ui and the REST api. It takes at least 10 minutes before the availability is actually sent.

Relevant forum post: https://forums.couchbase.com/t/fts-service-for-couchbase-takes-a-long-time-to-show-up-in-cluster-configuration/22298

[rishabh]

I haven't had any traction on that forum post I made so I'm going recommend disabling the test for Search queries for now. Please try running the Couchbase server for at least 15 to 20 minutes before running the Search query tests, otherwise they will fail with the error message Operation not supported.

[rishabh]

I'm hitting some compiler errors when compiling libcouchbase, which might be the reason why I can't get the tests to run for both 2.4.0 and >=2.4.0. I'll investigate further.