api.md: remove Lua API: CLI, raft_get_index, pico.args

Summary

• api.md: remove Lua API: ACL + raft_get_index

  Address changes from picodata!1191 (merged)

• api.md: remove pico.args

  Address changes from picodata@8d6bc587 (24.2.0-66-g8d6bc587)

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• Close #322 (closed)
• Cherry-pick to: none
• Staging: https://docs.binary.picodata.io/picodata/asabirov_remove_lua_api_functions/reference/api/