Updated how BPF assets are embedded. Missing object files will now be a
runtime error instead of a build time error. However, this will allow
teleport/lib to used as a module because tools like "go mod vendor" were
failing when attempting to vendor teleport/lib due to the missing object
files.
Added bytecode directory with README.md so "go:embed" does not complain
about missing assets. This allow developers to checkout Teleport and
work on it without needing libbpf or any other BPF tooling.
