Add support for command `ZCOUNT`

[JyotinderSingh]

Add support for the ZCOUNT command in DiceDB similar to the ZCOUNT command in Redis. Please refer to the following commit in Redis to understand the implementation specifics - source.

Write unit and integration tests for the command referring to the tests written in the Redis codebase 7.2.5. For integration tests, you can refer to the tests folder. Note: they have used TCL for the test suite, and we need to port that to our way of writing integration tests using the relevant helper methods. Please refer to our tests directory.

For the command, benchmark the code and measure the time taken and memory allocs using benchmem and try to keep them to the bare minimum.

[swarajrb7]

@JyotinderSingh can I pick this issue

[JyotinderSingh]

@JyotinderSingh can I pick this issue

Since you are assigned another issue already, let's allow others to pick this one up.

[tarun-29]

please assign this to me

[JyotinderSingh]

please assign this to me

Assigned.

[tarun-29]

Pull request which closes this issue https://github.com/DiceDB/dice/pull/1171

[apoorvyadav1111]

Linking #1158: depends on this for integration tests