Replace installDevSpaces*.sh with dsc installer / can I pass a specific IIB to dsc to install a specific catalog source / Dev Spaces version?

Since CRW-3897 now works, we may want to simply strip https://github.com/redhat-developer/devspaces/blob/devspaces-3-rhel-8/product/installDevSpacesFromLatestIIB.sh down to be two steps:

• install dsc for a given version, eg.

  DSC_VERSION="3.5.0-CI"; DSC_ARCH="linux-x64"
  DSC_HOME=${HOME}/.dsc; mkdir -p "${DSC_HOME}"
  DSC_TGZ_URL="https://github.com/redhat-developer/devspaces-chectl/releases/download/${DSC_VERSION}-dsc-assets/devspaces-${DSC_VERSION%-*}-dsc-${DSC_ARCH}.tar.gz"
  curl -sSkLo- "${DSC_TGZ_URL}" | tar -zx -C "${DSC_HOME}/" --strip-components 1 
  if [[ -d ${DSC_HOME}/bin ]]; then \
    export PATH=${PATH%":${DSC_HOME}/bin"}:${DSC_HOME}/bin; echo -n "Installed: "; dsc version; \
  else \
    echo "An error occurred installing dsc $DSC_VERSION for arch $DSC_ARCH ! Check if ${DSC_TGZ_URL} is a valid file."; \
  fi
  

• install devspaces from a given quay IIB

  dsc server:deploy --olm-channel=latest
  # or
  dsc server:deploy --olm-channel=next

This means the script won't work for custom/special IIBs or other cases.

So at minimum we would need a flag added to `dsc server:deploy` to allow passing in a specific IIB URL, rather than just `latest` or `next`.