MCU_Microchip_PIC18 is inconsistent

[cpresser]

While working on #2013 I tried to find some reference by looking at similar devices.
Most of the devices in the lib have at least one of those issues:

• Name is wrong: PIC18LF45K50_QFP (should be -ML)
• MCLR-Pin position differs (top left, or in line with PortE, bottom left, ...)
• MCLR-Pin names differ
• VUSB not on top for most devices (PIC18F2450-IML)
• Pins not ordered in a sane manner (PIC18F24K50-xML)
• Symbol-Body to big (PIC18F24K50-xML)
• NC-Pins not on symbol outline (PIC18F4458-IML)

I think this is a real mess, but am not sure how to fix it.
One approach would be to use something like https://github.com/erichVK5/BXL2text together with the .bxl files provided by microchip: https://www.microchip.com/development-tools/reference-designs/cad-cae-symbols
Not sure about licensing, I will try to investigate.

[evanshultz]

Please see #387. I believe a lot of the items are similar. This issue might be able to be swept into that issue, which covers all Microchip MCU libs.