Remove dependency on protobufjs

From the [private thread discussing the issue](https://filecoinproject.slack.com/archives/C02BZPRS9HP/p1664366203595479)

> protobufjs is big, complex, uses eval and has circular dependencies
>
> 

Seem like there is even viable alternatives out there https://github.com/timostamm/protobuf-ts

Ideally we won't even pull in the peps here and go with approach @rvagg did in https://github.com/ipld/js-dag-pb/blob/master/src/pb-encode.js

Start by reviewing the current protobufjs dependency and the referenced js-dag-pb implementation at src/pb-encode.js, then compare the suggested protobuf-ts alternative. Done means protobufjs is no longer pulled in and UnixFS protobuf encoding continues to work with the chosen replacement.

Written by the indexing model from the issue text.