Password in credentials.json isn't properly escaped

[kuba-orlik]

Describe the bug

If a users chooses a password that conains a ", then the credential.json is not a valid JSON and the app doesn't start

Context

• Hardware: VPS bought online
• YunoHost version: 4.3.5
• I have access to my server: Through SSH
• Are you in a special context or did you perform some particular tweaking on your YunoHost instance?: no
• Using, or trying to install package version/branch: 1.8.16~ynh2

Steps to reproduce

• Install the app
• When asked for admin password, enter a password that contains a "
• Finish the installation
• Restart the server
• See that the app didn't start and just gives 502 error

Expected behavior

The " char should be properly escaped

Logs

[2022-02-17 13:01:06.677] [INFO] settings - All relative paths will be interpreted relative to the identified Etherpad base dir: /var/www/etherpad_mypads
[2022-02-17 13:01:06.695] [INFO] settings - settings loaded from: /var/www/etherpad_mypads/settings.json
[2022-02-17 13:01:06.696] [ERROR] settings - There was an error processing your credentials file from /var/www/etherpad_mypads/credentials.json: Unexpected token Q in JSON at position 196

[ericgaspar]

https://github.com/YunoHost-Apps/etherpad_mypads_ynh/pull/163 should address this issue. to be tested