Follow-up from #1716: it should be possible to externally add libraries with @Owning / @NotOwning in suitable locations.

I will try to blend this into the existing support for .eea files.

eea for null analysis uses this encoding:

• 0 = @Nullable
• 1 = @NonNull

Without modifying the general format, we still have the digits 2-9 for encoding more annotations. While there is no intuitive mapping like 0/1, I think using 8/9 is a pragmatically valid option, that still leaves us with the option to use 2 for another null related annotation etc. (Should we ever run out of digits, we can still change the format to let digits start a multi char encoding etc. - but not for now).

Technically we need to check if the existing integration via TypeAnnotationWalker can suitably "simulate" owning annotations in declaration positions. Let's see whether having @Owning specify TYPE_USE as one of its targets works for or against this strategy.