allow _ in stream name

broker/src/asapo_broker/database/mongodb_streams.go

broker/src/asapo_broker/database/mongodb_test.go

broker/src/asapo_broker/database/streams_test.go

broker/src/asapo_broker/server/get_commands_test.go

broker/src/asapo_broker/server/get_streams.go

common/go/src/asapo_common/utils/helpers.go

common/go/src/asapo_common/utils/helpers_test.go