Implement a way to permanently store changeable media/RTC settings and change the entire VM for one time

[Tech-FZ]

The Discord user lewellyn has requested a feature to be able to leave RTC time on permanently. This means we will have to restructure EmuGUI a little.

Changes on the New/Edit VM dialog

• Implement floppy, cdrom, boot order and time settings to be saved permanently
• Make the Edit VM dialog able to be utilised for one-time changes as well

Changes on the Start VM dialog

• Remove all settings (except for TPM).
• Add an "One-Time Edit" button to do what described above.

Scripts which will be added

• The code for actually starting the VM would be moved to a different file.

Notes for SWTPM users: Migrating the TPM settings as described above is a little difficult. I can try doing so anyway, but I can't guarantee anything. For now, assume that TPM settings will remain a sole one-time setting.

[Tech-FZ]

One-time edit doesn't work yet.