Added another new test. Uses only AdminAPIs since the focus is high availability

[vipbhardwaj]

A high availability test is a migration of this

I small nitpick : I have not been able to verify the last part, ie, _expvar . I went through the whole thing twice and came to the current conclusion which is that this last step doesn't contribute a lot to the test's intention.
But if it does then please give me a better way to use the _expvar endpoint to serve the last step's intention.

[RIT3shSapata]

I think you misunderstood the test case, I've pointed out what should be done instead in my comments.

Regarding the expvar endpoint is used to get the metrics of SGW. So you can either use the same expvar endpoint, which is now currently used a debug endpoint. But the right way would be to use the metrics API to get the specific metrics and validating it. From the previous test description, I see the following metrics have to be checked:

7. Verify stats
   EE - import_cancel_cas =0
   - import_count = num of docs
   CE - import_cancel_cas is not equal to 0
   import_count + import_cancel_cas = num_docs

[borrrden]

I'm going to wait for the results of Ritesh's review

[vipbhardwaj]

I'm going to wait for the PRs #322 and #323 to merge and resolve their conflicts and update remote main and start from there. 😭
CC @borrrden @RIT3shSapata

[borrrden]

I defer to Ritesh for this review. It's entirely SGW related testing