[Epic] CDC tech debt

[lenkis]

PM ref.:

• CDC in Jira: https://jira.vk.team/browse/PRODUCTS-679
• CDC in Confluence: https://confluence.vk.team/display/TSE/Tarantool+CDCv9?src=contextnavpagetreemode
• CDC in GitLab: https://gitlab.corp.mail.ru/tarantool/cdc/v9/tarantool-cdc
• CDC dev docs:
  • Dev docs in md: https://gitlab.corp.mail.ru/tarantool/cdc/v9/tarantool-cdc/-/tree/master/doc
  • Anna Balaeva's readme: https://gitlab.corp.mail.ru/tarantool/k8s/helm-chart-cdc

SME: @ dkasimovskiy

Doc draft deployed here: https://docs.d.tarantool.io/ru/cdc/doc/doc-draft/

Details

We need to finalize the initial draft of our doc set.

Doc set parts:

• CDC: Reference > Metrics: review #4990
• CDC: Admin guide #4589