`compare` function implementation

[YarShev]

So far, we are just defaulting to pandas.

[anmyachev]

Default implementation of the function was be added by #1840.

Distributed implementation should be added in another PR.

[kvu35]

@anmyachev @devin-petersohn I think this API can be implemented using a process similar to binary op in the query compiler level. Hope it's all right if I work on this and open a PR.

[anmyachev]

Thanks @kvu35!
This will be very helpful for us.