refactor: remove Lua API functions

Summary

• refactor: remove Lua API pico.create_table
• refactor: remove Lua API pico.drop_table
• refactor(luamod): remove unused functions
• refactor: remove Lua API pico.raft_wait_index
• refactor: remove Lua API pico.raft_read_index
• chore: bump LUA_API_VERSION
• chore: update CHANGELOG.md

Changes:

• pico.create_table — CREATE TABLE
• pico.drop_table — DROP TABLE
• pico.raft_read_index — .proc_read_index
• pico.raft_wait_index — .proc_wait_index

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• Part of docs#263
• Cherry-pick to: none
• Docs follow-up: not necessary
• See also:
  • !1191 (merged)
  • Google Sheets — RPC API