revisit sdp local code gen

[DavidS-ovm]

Address the symlink issue papered over in #298

[tphoney]

How sdp 'npx buf generate' works .
in the gen folder there are symlinks to both the sdp-go and sdp-js.
when generates completes the symlink for sdp-go is broken, sdp-js is ok.
this means that no changes made in sdp, are propagated through to any of the go projects.

there are 2 config files for "npx buf" buf.gen.yaml and buf.yaml.
we use a plugin to generate the go, maybe this is the smoking gun.

version: v2
clean: true
plugins:
  - local: protoc-gen-go
    out: gen/sdp-go
    opt: paths=source_relative
  - local: protoc-gen-connect-go
    out: gen/sdp-go
    opt: paths=source_relative

[tphoney]

way to test
'npm install' needs run at least once

ls -alh gen
npx buf gen
ls -alh gen

[tphoney]

a potential work around temporarily, would be to downgrade the buf library for go usage

[tphoney]

@dylanratcliffe now could be the time to split out sdp-go private code and generated code. might be worth the experiment.
sdp-js could stay the same.

sdp-go private code could move into api-server. but that may cause circular dependencies with gateway

[dylanratcliffe]

This has been fixed by just changing the generation location to ../ rather than ./gen. That way it still works within the workspace, and I just adjusted the release script to match