test: solve issue on impossibility to run e2e tests in docker

- Add details in README on how to correctly install npm dependencies
- Modifiy protractor.config.js to solve issue with the error message "unknown error: session deleted because of page crash" (Solution found in https://stackoverflow.com/questions/53902507/unknown-error-session-deleted-because-of-page-crash-from-unknown-error-cannot)

README.md

@@ -6,6 +6,10 @@ See also [developers documentation](DEVELOPERS.md) (in french)
 
 ### Requirements
 
+Requirements for developping Cassiopee can be achieved by manually install the required dependencies on your computer or by using the dedicated docker container.
+
+#### Required dependencies
+
  * [jalhyd](https://gitlab.irstea.fr/cassiopee/jalhyd)
  * npm
  * python3
@@ -25,6 +29,12 @@ Building the PDF documentation requires pandoc and a LaTeX distribution (for ex.
 sudo apt install pandoc texlive latexmk texlive-latex-extra texlive-bibtex-extra
 ```
 
+#### Using docker container
+
+Download and use the following docker image: https://hub.docker.com/repository/docker/geaucassiopee/ci-cd-cross-platform-webapp
+
+More details on how to use it on vscode are available at https://gitlab.irstea.fr/cassiopee/cassiopee2-integration
+
 ### Install dependencies
 
 #### JaLHyd
@@ -40,9 +50,11 @@ npm run package
 Then in `nghyd` folder, run :
 
 ```sh
-npm install
+npm ci --force --unsafe-perm
 ```
 
+This installs the exact same version of dependencies as the ones specified in `package.lock.json`.
+The parameter `--unsafe-perm` solves permissions issues for running e2e tests in a docker container.
 
 ### Compile and get a deployable Web app
 

protractor.conf.js

@@ -37,11 +37,12 @@ exports.config = {
       args: [
         "--no-sandbox",
         "--headless",
-        "--window-size=1024x768"
+        "--window-size=1024x768",
+        "--disable-dev-shm-usage"
       ],
       prefs: {
         download: {
-            prompt_for_download: false, 
+            prompt_for_download: false,
             directory_upgrade: true,
             // default_directory: '/tmp/e2e-downloads'
         },