New options for instance create & handle nvram & migrate options

[catborise]

hi retspen,

There are many additions, bug fix, and enchancements:

1. Big one is instance creation: Choosing firmware, chipset, and machine types are possible...
2. Delete addition: delete instance that has nvram
3. Migrate: rewrite migrate function: handle compress, postcopy and autoconverge
4. Options to settings: User can add some keywords to domain disk xml, machine type, vcpu model
5. Clone: handle nvram while cloning instances.
6. Requirements update
7. Typo fixes and some error fixes and more

thanks

[retspen]

Awesome. Thank you!