Penv-442: pulse comparator

[sofiayem]

pulse_comparator is a script that sends identical "transactions-in-pulse-number-range" requests to MainNet and local node's APIs, compares results, and saves both the request and result (or diff) in a file for future manual query and comparison via copy-paste.

Test the "no diff" case (expected):

1. Bring up the local node against a dev environment.
2. Set the MainNetURL value (in const) to the dev environment's public read-only API endpoint.
3. Run the script as follows:
   go run pulse_comparator.go <from_some_pulse_number_in_dev_env> <to_some_pulse_number_in_dev_env> <limit> <dev_env_API_endpoint>

Test the "diff" case:

1. Comment line 88 and uncomment lines 91 and 92.
2. Perform all the steps from the previous case.