Enhance documentation for initial setup

[denisosteo]

Being struggling for 2 days in building the repository, I would suggest to enhance install documentation.

Main issue is repetitive "fetch-pack: unexpected disconnect while reading sideband packet" during git clone. Either to load initial https://github.com/juliusknorr/nextcloud-docker-dev. Or when running bootstrap script.

Documentation should make it more clear that the steps: git config --global core.compression 0 git clone --depth 1 https://github.com/juliusknorr/nextcloud-docker-dev git fetch --unshallow

Recommand to make backup copy nextcloud-docker-dev cp -r nextcloud-docker-dev nextcloud-docker-copy before to run bootstrap script This allow to restart without struggling again to download repository in case of failure during execution of bootstrap scrip.

Also the way to edit bootstrat script to make git clone safer. Or provide an alternate bootstrap script to make git clone safe