Add devcontainer.json to ease local dev environment setup (#13638)

* Added devcontainer.json

Added devcontainer.json

* Moved file to devcontainer folder

Moved devcontainer.json to devcontainer folder

* Documented Dev Container setup in README

Section 'Using Docker Image' rephrased to include Dev Container setup documentation

* Added back the original section 'Using Docker Image'

Dev Container section separated from Docker Image section

---------

Co-authored-by: Trig <7973740+Trigtrig@users.noreply.github.com>

.devcontainer/devcontainer.json

@@ -0,0 +1,9 @@
+// https://containers.dev/implementors/json_reference/
+
+{
+  "name": "selenium-devcontainer",
+  "build": {
+    "dockerfile": "../scripts/dev-image/Dockerfile"
+  },
+  "runArgs": ["--name", "selenium_devcontainer"]
+}

README.md

@@ -101,13 +101,19 @@ Rather than creating your own local dev environment, GitPod provides a ready to
 
 [![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/SeleniumHQ/selenium)
 
+#### Using Dev Container
+
+As an alternative you can build a [Dev Container](https://containers.dev/) - basically a docker container -
+suitable for building and testing Selenium using the devcontainer.json in the
+[.devcontainer](.devcontainer/devcontainer.json) directory. Supporting IDEs like VS Code or IntelliJ IDEA
+should point you to how such a container can be created.
+
 #### Using Docker Image
 
 You can also build a Docker image suitable
 for building and testing Selenium using the Dockerfile in the
 [dev image](scripts/dev-image/Dockerfile) directory.
 
-
 ## Building
 
 Selenium is built using a common build tool called [Bazel](https://bazel.build/), to