Add documentation on how to add new projects

Author: furtib

test/foss/README.md

@@ -0,0 +1,9 @@
+# How to add a new project:
+
+- Create a folder with the name of the project.
+- place an init.sh script in the folder, this script should:
+  - Clone the test project into a folder named `test-proj`.
+    - To ensure the project doesn't change over time, check out a specific tag or commit instead of a branch!
+  - Copy the .bazelversion file from the templates directory.
+  - Append the WORKSPACE.template file to the WORKSPACE file of the project.
+  - Append the codechecker rules to the BUILD file of the project.