Improve PE File & Program Icon Loading

[divadretlaw]

PEFile Improvements

• Close FileHandle after parsing
• Split types into multiple files
• Add some documentation
• Fix OptionalHeader not differentiating PE32 and PE32+
• Interpret more values while parsing (maybe a bit overkill, but they could be useful in the future or other projects trying to access values of a PE file)
• Improve Icon Loading

I think it would be best to cache the icons as it seems to take a bit to load them to find the best / largest one.

I would recommend https://github.com/kean/Nuke but there are many options and even the possibility to create a cache without any dependencies if that is desired.

Adding a dependency should be the decision of the maintainer and if they think adding a cache, and also which library to use if any, then I would be happy to implement that as well.

[IsaacMarovitz]

Most of the improvements to PE parsing that I'm seeing here are not relevant. The parsing implementation used was designed to be a bit naive, as we really only need the data present in the resource table for our purposes. If we wanted to create a more complete implementation, as is shown here, it might be worth splitting it into a separate project/swift package.

[divadretlaw]

That approach makes sense, I reverted the not-needed changes to the PE parsing