provide archives of foreign git repositories via http(s)

Installation:

- change ownership of "work" to webserver user
- point a php-capable webserver to httpdocs
- run clone-repos as webserver user by cronjob or similar
- run update-repos as webserver user by cronjob or similar

Use:

access on the webserver:

- to schedule for cloning
  ?r=base64_encode(https://url.to/upstream/repository.git)

- to retrieve tar ball:
  ?r=base64_encode(https://url.to/upstream/repository.git)&tag=base64_encode(tag)
  ?r=base64_encode(https://url.to/upstream/repository.git)&commit=hash