tests: fully switch to deps.edn

[lread]

In support of #18 (comment)

There is some minimal support for running tests via Clojure cli from bb tasks, but because not all test namespaces do not end in -test only a subset of tests are being run. Will adjust runner.

Will also freshen outdated deps.

And delete project.clj to avoid any confusion.

[lread]

Our tests are using an old version of ring/ring-jetty-adapter which brings in jetty v7 which was retired in 2014.

This tech is used to prop up a server for tests to hit.

There might be some value in updating it, but I'll consider this out of scope for this issue.

[borkdude]

Agreed