easy-installer: Improve install zipped recovery scripts

Description

// Describe what the MR bring

Issue(s)

https://gitlab.e.foundation/e/backlog/-/issues/7776

Test environment

• non regression test

/!\ Checked OS should at least be tested: /!\

• windows
• linux
• MacOS Not supported yet_

Check list

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