TCS: remove prepare from sql

[lenkis]

Related dev. resources:

• TCS roadmap: https://www.notion.so/tarantool/TSC-933d545852824f5abefa189881a801a8#add621ee191e438d91bb27bf19638159
• TCS releases Q2-Q3: https://www.notion.so/tarantool/TCS-Q2-Q3-2024-2844bf3db1184e7c939686e2ea0c9362

Product: TCS
Since: product version
Audience/target: who will read it and for what task?
Root document: where to add or update documentation
SME: @ Galiev-Ruslan

Details

• remove prepare from /sql
• document prepare for /computation

[lenkis]

Closed by https://github.com/tarantool/tcs-doc/commit/cc55219439f7376656f6ed5e48127d460e9ee80e