FP3: Simplify installation steps

Description

Simplify steps for FP3 installation via bootloader

Issue(s)

https://gitlab.e.foundation/e/devices/backlog/-/issues/159

Test environment

git checkout <branch-name>
docker run --rm --volume="$PWD/htdocs:/srv/jekyll" -d -p 4000:4000 --name e_documentation_v3 jekyll/jekyll:4.2.0 jekyll serve

Then connect to http://localhost:4000/

At the end of the test, run the following command to stop the Docker container

docker stop e_documentation_v3

Check list

• Self review
• Test procedure explained
• Tested on fresh install
• Tested applied as an update
• License
• Internal documentation
• User documentation

Closes #159