Stop asset_price_pairs cryptocompare exporter

[IvanIvanoff]

It exports all prices and volumes into a kafka topic that has never been
used, but is very large. We still have asset_price_pairs_only which
exports only the prices, which are in active use.

Changes

Ticket

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have tried to find clearer solution before commenting hard-to-understand parts of code
• I have added tests that prove my fix is effective or that my feature works