Clarify CHC usage / pricing

[aashishkohli]

Evaluate places in our docs to clarify CHC (clickhouse cloud credits) usage in our docs and potentially in the MP listings on AWS, GCP, Azure. It looks like some customers are getting confused that paying for CH cloud is more expensive through the marketplace.

context: https://clickhouse-inc.slack.com/archives/C04TML9DVE3/p1724855790944129

Some sections to potentially add this clarification to:

• https://clickhouse.com/docs/en/manage/billing
• https://clickhouse.com/docs/en/cloud/marketplace
• MP listings on all 3 clouds

cc: @justindeguzman , @minodudd , @hans-bakker-clickhouse

[hans-bakker-clickhouse]

As a quick fix, can we add a link to the pricing calculator in the pricing section?