Alternative to pihole checkout

[PromoFaux]

Install script is not run so the options are:

• monkeypatch the functionality of pihole checkout into the container and customise the code
• drop support for switching branches (This might be better, it's easy enough to build a new container on a custom branch)

[DL6ER]

The later does indeed sound better and a lot less likely to break in unexpected ways

[PromoFaux]

the build.sh script included in the repo makes this trivial