moved session to namespace query and move basic_schema::initialize to session constructor

include/matador/sql/query_context.hpp

@@ -29,12 +29,6 @@ enum class sql_command {
   AlterSchema
 };
 
-enum class return_mode {
-  None,
-  GeneratedKeys,
-  Rows
-};
-
 struct query_context {
   std::string sql;
   size_t sql_hash{};
@@ -48,14 +42,10 @@ struct query_context {
   // Data for resolving query result
   std::shared_ptr<resolver_service> resolver{};
   std::type_index result_type = typeid(void);
-  return_mode mode = return_mode::None;
 
   [[nodiscard]] bool is_ddl() const { return command == sql_command::Create || command == sql_command::Alter; }
   [[nodiscard]] bool is_dml() const { return command == sql_command::Insert || command == sql_command::Update || command == sql_command::Delete; }
   [[nodiscard]] bool is_query() const { return command == sql_command::Select; }
-
-  [[nodiscard]] bool expects_rows() const { return mode == return_mode::Rows; }
-  [[nodiscard]] bool expects_generated_keys() const { return mode == return_mode::GeneratedKeys; }
 };
 }