Add collector(s) for git information

[lbianchi-lbl]

Targets

• GitRepository collector
• Possibly connected with PythonDistribution, e.g. if editable, try to collect

Contents

• git log (in a suitably compact format)
  • Current branch
  • Current commit
• information about uncommitted/unstaged files via git status or similar)
• Remotes
  • Possibly GitRemote collector
• Repository activity
  • e.g. last pulled