Check for correct handling of negative offsets

[holzkohlengrill]

Description

When entering a negative offset in the configuration (addressSpaces.json) check if this is handled correctly.

{
    "offset": "<NEGATIVE_ADDRESS>",
    "memory": {
...

Expected behaviour

• Negative resulting addresses should be skipped and a warning should be shown
• The offset should be handled signed (-> a negative offset is added; a positive offset subtracted)