Container image builds don't work with git worktrees

[tnozicka]

When you set up a git worktree the .git folder is something like a "symlink" to the original directory

git worktree list
/home/tnozicka/dev/go/src/github.com/scylladb/scylla-operator    db74ccf1b [fix-openshift]
/home/tnozicka/dev/go/src/github.com/scylladb/scylla-operator-1  32f8fa4d6 [git-worktrees]

$ cat /home/tnozicka/dev/go/src/github.com/scylladb/scylla-operator/.git
cat: /home/tnozicka/dev/go/src/github.com/scylladb/scylla-operator/.git: Is a directory

$ cat /home/tnozicka/dev/go/src/github.com/scylladb/scylla-operator-1/.git
gitdir: /home/tnozicka/dev/go/src/github.com/scylladb/scylla-operator/.git/worktrees/scylla-operator-1

Without containerization that works fine but container image builds require a build context and the tar only the local "scylla-operator-1" directory which contains only the .git "symlinks" which lacks the source in the build container.

We should allow builds from source code without git in general and fix this as well.