(ui): postgres ha cluster - extensions

Please add a form "Extensions" similar to "Advanced options" that opens when clicked.

• Extensions (the list of parameters opens when click)
  • pg_repack (checkmark (active by default))
  • pg_cron (checkmark (active by default))
  • pgaudit (checkmark (active by default))
  • pgvector (checkmark (active by default)) - not displayed for Postgres 10
  • postgis (checkmark (not active by default))
  • pgrouting (checkmark (not active by default))
  • timescaledb (checkmark (not active by default)) - not displayed for Postgres 10, 11
  • citus (checkmark (not active by default)) - not displayed for Postgres 10
  • pg_partman (checkmark (not active by default))
  • pg_stat_kcache (checkmark (not active by default))
  • pg_wait_sampling (checkmark (not active by default))

Variable: enable_<extension_name>=true. Where "<extension_name>" is the name of the selected extension from the form. Add a variable to the snippet only for selected extensions.

Place it in front of the "Advanced options" form