feat(sql): mock transaction control commands: begin, commit, rollback

sbroad/sbroad-cartridge/src/api/exec_query.rs

sbroad/sbroad-cartridge/test_app/test/integration/tcl.lua

sbroad/sbroad-core/src/backend/sql/ir.rs

sbroad/sbroad-core/src/backend/sql/tree.rs

sbroad/sbroad-core/src/executor.rs

sbroad/sbroad-core/src/executor/ir.rs

sbroad/sbroad-core/src/frontend/sql.rs

sbroad/sbroad-core/src/frontend/sql/query.pest

sbroad/sbroad-core/src/ir.rs

sbroad/sbroad-core/src/ir/api/parameter.rs

sbroad/sbroad-core/src/ir/block.rs

sbroad/sbroad-core/src/ir/expression/types.rs

sbroad/sbroad-core/src/ir/node.rs

sbroad/sbroad-core/src/ir/node/tcl.rs

sbroad/sbroad-core/src/ir/tree/expression.rs

sbroad/sbroad-core/src/ir/tree/relation.rs

sbroad/sbroad-core/src/ir/tree/subtree.rs

src/pgproto/backend.rs

src/pgproto/backend/describe.rs

src/pgproto/backend/pgproc.rs