* build: add prom-client to data-transport-layer

* refactor: thread metrics more carefully through data-transport-layer; add two new metrics

* style: fix some style issues

* refactor: make metrics mandatory

* refactor: move metrics register code to top of file

* style: apply linting

* refactor: move promethesus initialization after express

* refactor: move promBundle call up, provide registry

* build: add changeset