Awesome dagPB.DAGNode API

[daviddias]

Tracking issue for updating and upgrading all the modules that use dagPB (ipld-dag-pb)

With the introduction of WebCrypto, the dagPB APIs suffered considerably, however, as exposed by ipld/js-ipld-dag-pb#4 it doesn't have to be this way and it is what ipld/js-ipld-dag-pb#6 is here to bring.

Name	PR	CR	M	R
js-ipld-dag-pb	✔️	✔️	✔️	✔️
js-ipld-resolver	✔️	✔️	✔️	✔️
js-ipfs-unixfs-engine	✔️	✔️	✔️	✔️
interface-ipfs-core	✔️	✔️	✔️	✔️
js-ipfs-api	✔️	✔️	✔️	✔️
js-ipfs	✔️	✔️	✔️	✔️