Keep root password and SSH authorized keys on firmware regenerations (#383)
Keep private keys when regenerating firmware (#383)
Fix NodeBuildFile unique constraint (#383)
Include private keys into node firmware config (#383 note-20)

* Show stored private keys on firmware download.
* Allow providing private keys on firmware generation,
    loading the stored ones if exists.
Refactor NodeBuildFiles: show in node change view (#383)
[firmware] Include help text in NodeBuildFileInline (#383)
Merge branch 'feature383': keep keys when regenerating firmware (#383)