Stand up gitweb as interim web view

Stand up gitweb as interim web view

Gitweb ships with git (already built from source), so adding it is
just a build step, lighttpd, perl, and two config files. The container
entrypoint is now lighttpd instead of quire serve — SSH dispatch via
docker exec still works since quire stays on the PATH.

All gitweb additions are tagged TODO(vys) for easy grep when the
native web view replaces them.

Assisted-by: GLM-5.1 via pi