Optimize pest grammar

sbroad-benches/Cargo.toml

sbroad-benches/benches/parse.rs

sbroad-core/src/frontend/sql.rs

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

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

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

sbroad-core/src/ir/expression.rs

sbroad-core/src/ir/operator.rs

...ts/artifactory/frontend/sql/arbitrary_projection_ast.yaml

...s/artifactory/frontend/sql/arithmetic_projection_ast.yaml

...ts/artifactory/frontend/sql/arithmetic_selection_ast.yaml

sbroad-core/tests/artifactory/frontend/sql/simple_query.yaml

...tests/artifactory/frontend/sql/single_quoted_str_ast.yaml

...re/tests/artifactory/frontend/sql/transform_select_2.yaml

...re/tests/artifactory/frontend/sql/transform_select_3.yaml

...artifactory/frontend/sql/transform_select_3_group_by.yaml

...s/artifactory/frontend/sql/transform_select_3_having.yaml

...sts/artifactory/frontend/sql/transform_select_3_join.yaml

.../tests/artifactory/frontend/sql/transform_select_4_1.yaml

...artifactory/frontend/sql/transform_select_4_having_1.yaml