File checks for config generation

[Dashboy1998]

Context

• set palworldsettings via envsubst and templating #207 removed the error handling when creating the INI file
• Added exiting on error during compile settings

Choices

• Moved helper functions to their own script so they can be used in other scripts

Test instructions

1. Verify the container starts as normal
2. Remove the write permissions of the config file chmod ugo-w palworld/Pal/Saved/Config/LinuxServer/PalWorldSettings.ini
3. Start the container and verify you get this message /palworld/Pal/Saved/Config/LinuxServer/PalWorldSettings.ini is not writable. and Unable to create /palworld/Pal/Saved/Config/LinuxServer/PalWorldSettings.ini
4. Delete the config file and remove write permission from the directory rm -f palworld/Pal/Saved/Config/LinuxServer/PalWorldSettings.ini && chmod ugo-w palworld/Pal/Saved/Config/LinuxServer/
5. Start the container and verify you get these messages /palworld/Pal/Saved/Config/LinuxServer is not writable. and Unable to create /palworld/Pal/Saved/Config/LinuxServer/PalWorldSettings.ini
6. Delete the config directory and remove the write permissions of the parent folder chmod ugo+w palworld/Pal/Saved/Config/LinuxServer/ && rm -rf palworld/Pal/Saved/Config/LinuxServer/ && chmod ugo-w palworld/Pal/Saved/Config
7. Start the container and verify you get this messages mkdir: cannot create directory '/palworld/Pal/Saved/Config/LinuxServer': Permission denied

Checklist before requesting a review

• I have performed a self-review of my code
• I've added documentation about this change to the README.
• I've not introduced breaking changes.