qmi-codegen API updates
Two main changes are implemented:
- "struct" elements can only be used exclusively as array elements, there is no possibility any more to use "struct" e.g. as a TLV ("sequence" would be the way to go for TLVs).
- "array" elements cannot contain "array" elements right away, they need an intermediate "struct"
These two changes prepare the ground for the new GIR compatibility methods involving arrays and structs.