Handle as many formats as possible when parsing dates

[maeb]

Based on real world testing on data from the early 2000's we need to replace the following code

https://github.com/nlnwa/warchaeology/blob/ab32b5f0340bc6b44ded32960c8fe1dbbcefe29c/nedlibreader/nedlibreader.go#L58-L66

with a function that can parse as many date formats as possible.