Testing 0.3.8~ynh3 / Improve systemd hardening

[OniriCorpe]

Problem

• https://github.com/YunoHost/example_ynh/pull/180

Solution

• Apply it (except for ProtectKernelLogs=yes wich is not available for now on ynh stable (yunohost 11.0.9.5 systemd 247.3-7))

PR Status

• [x] Code finished and ready to be reviewed/tested
• [ ] The fix/enhancement were manually tested (if applicable)

[yunohost-bot]

Alrighty!

[OniriCorpe]

note to self: test this change on my test instance