Add dynamic hostname setting based on MAC address

[dsbilling]

Introduced functions to retrieve the MAC address and set the system hostname to the app name plus the last 4 characters of the MAC address. This ensures unique hostnames for each device during installation.

This ensures each device has a unique hostname during installation, preventing network conflicts and making devices easily identifiable.

[dsbilling]

@fatihak Adding the "set hostname" in the update.sh file might be too destructive. What do you think?

[fatihak]

Wondering if it might be more straightforward to have an optional argument to the install script to set a custom hostname instead?

[fatihak]

Haven't heard back, I also think updating the host name after an update would be destructive and confusing. I would be open to having an argument in the install/update scripts to be able to set a custom hostname instead.