gitlab-ci and readme need to be updated

Remove user ownership and add executable permission to build-install-openresty-voms script.

Use both provide-deps.sh files in devcontainer:
 * provide-CI-deps.sh install the deps for CI
 * provide-dev-deps.sh install the remaining deps for the devcontainer

Before this update, provide-CI-deps.sh was a subset of provide-dev-deps.sh

Use name conventions in .devcontainer

The build-install-openresty-voms.sh script is copied in /usr/local/bin instead ~/bin.

Deleted the addition of ~/bin from PATH env variable.

DEV_USER -> USERNAME
DEV_USER_UID -> USER_UID
DEV_GID -> USER_GID

See the best practise:
https://github.com/microsoft/vscode-dev-containers

All the file in assets used tu build the devcontainer are moved in library-script.

Modify the Dockerfile COPY directory

The patch file used by the .devcontainer is needed only by  the build-install-ngx-voms.sh script. This script could use the patch file in the project home dir instead of the copy in the container.

Add an echo in the container specifing that the patch file must exists in the directory where the user runs the script.

Add  a check in the script: if the patch file isn't found, the script adivses the user and exits with an error.

Replace 'VSCODE' with a more general 'DEV'

To create the image defined in this dockerfile, we've merged three differend images:
 * storm2/build/base
 * storm2/build/ngx-voms-build [issue-17]
 * storm2/ngx_http_voms_module/.devcontainer
Each image has this own 'yum install' command with the packages needed for that layer.

With this commit, all the packages are installed in a single layer to reduce the image dimension.
All the 'yum install' commands are grouped in the setup.sh script.

* To reduce the image dimension, two RUN commands are merged in one single layer.
* All packages are installed with a single command.
* remove cern and garr mirrors
* the clean commands are the last instructions in the layer
* sudo is installed only in the dockerfile

As written in the best practise: https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#add-or-copy

To create the vscode user, the provide_user.sh script is used. With this script the comand line appearance is improved with colors and branch informations

Update the license format in Dockerfile as an example. These two lines need to be inserted in all the file in the project repo

Only one user is useful: test user and storm user have been removed. The default user has changed name in vscode because is the not-root user commonly used in devcontainer