Description of problem:

in air gapped environment, where github.com i not accessible it is not possible to build the che-plugin-registry using a fork of  https://github.com/redhat-developer/devspaces . as it tries to pull content from github.com

Prerequisites (if any, like setup, operators/versions):

no access to github.com

access to npm registry

access to Open VSX Registry (open-vsx.org)

access to quay, docker hub, redhat and google container regestries 

Steps to Reproduce

• download a zip of release branch such from https://github.com/redhat-developer/devspaces/tree/3.9.1. i.e.:
  https://github.com/redhat-developer/devspaces/archive/refs/tags/3.9.1.zip
• upload the zip content to air gap environment and extract
• run the following to build:
  ```
  cd devspaces/dependencies/che-plugin-registry
  ./build.sh
  ```
   

  Actual results:

{}{}

• getting the following error:
   
  ```
  --> 85a7cc51530
  STEP 3/11: RUN cd /tmp && git clone https://github.com/che-incubator/che-openvsx.git && cd che-openvsx/server && git checkout che-openvsx
  Cloning into 'che-openvsx'...
  fatal: unable to access 'https://github.com/che-incubator/che-openvsx.git/': OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443
  subprocess exited with status 128
  subprocess exited with status 128
  Error: building at STEP "RUN cd /tmp && git clone https://github.com/che-incubator/che-openvsx.git && cd che-openvsx/server && git checkout che-openvsx": exit status 128
  ```

   

•  

  Expected results:

able to build the plugin-registry image in air gapped environment

• Reproducibility (Always/Intermittent/Only Once): Always