hooks queried in <workdir>/.git/hooks

[extrawurst]

in order to implement #1044 we need to first clean up that hooks are currently read from <workdir>/.git/hooks/... this breaks as soon as someone uses the new --workdir arg and the hooks are placed in some other place inside .git.

[extrawurst]

we need to make sure the hooks still get the correct current-working-dir:

Before Git invokes a hook, it changes its working directory to either $GIT_DIR in a bare repository or the root of the working tree in a non-bare repository. An exception are hooks triggered during a push (pre-receive, update, post-receive, post-update, push-to-checkout) which are always executed in $GIT_DIR.