* deps: upgrade gogo-protobuf to v1.3.2
* go mod tidy using go 1.16
* proto: regen protobufs after upgrading gogo/protobuf
Co-authored-by: Daniel Nephin <dnephin@hashicorp.com>
Most of the groundwork was laid in previous PRs between adding the cert-monitor package to extracting the logic of signing certificates out of the connect_ca_endpoint.go code and into a method on the server.
This also refactors the auto-config package a bit to split things out into multiple files.
