Fix cross-compilation (#6441)

* Avoid packaging yarn.lock

Since the shrinkwrap is what we want everything to use.

* Build with npm

It seems we stuck with yarn because npm was giving us errors but I will try
sorting it out now so we can build with npm as originally intended.

* Remove build from source

Not using CentOS 7 anymore so based on the comment we no longer need
this.  Keytar seems to install fine now.

* Update missed Node version

These numbers are all over the place.

* npm_config_arch must be lowercase

* Patch out Kerberos

I am not sure exactly how it is used but I think it is not a path code-server
worries about, at least not right now.  Just going to patch it out rather than
figure out how to build it on armv7l but we can revisit later.