filecoin-pin in CI as a testing scenario for multi-copy upload + Synapse testing

[rvagg]

Part of FilOzone/filecoin-services#357; not yet solved by #90 (Edit: we have scenarios/test_storage_e2e.py now so it is supported, sorry, this is an extra layer that we need to do)

Devnet support got added in filecoin-pin in 0.18 in filecoin-project/filecoin-pin#354, so it should be mostly a matter of making some test data in the form of files, then either installing filecoin-pin or just running npx -y filecoin-pin@v0.18 add --network devnet /path/to/data substituting 0.18 for some other version or just @latest. Potentially also we can test a git clone and npm install then node dist/cli.js add --network devnet /path/to/data and get the same effect if we want to test the master branch.