Do not walk ignored directories

[nielsbasjes]

Followup of #124 where @vincentjames501 mentions this problem:

I noticed that on some of our larger java projects and especially large webapps/node projects the tool was taking forever. Turns out it's Files.find. It naively walks every folder even gitignored ones so when it walks a massive folder like node_modules/ or even some large target/ directories it can take forever. Just to test some things out, I found I could speed things up orders of magnitude by using Files.walkFileTree(path, new FileVisitor<>() {: https://github.com/vincentjames501/codeowners-cli/blob/main/src/main/java/org/vincentjames501/codeowners/commands/ListCodeOwners.java#L82
As this gives the ability to skip traversing ignored directories entirely. I don't like all this mutability and I'm sure it could be rewritten to be some recursive/lazy stream but wanted to get something working first.

Or simply put: An already ignored directory should be skipped in the finding of files.

[nielsbasjes]

File is now here https://github.com/vincentjames501/codeowners-cli/blob/f3aff8b95d3ecb97ab8210fa2f20a621e08fa47b/src/main/java/io/github/vincentjames501/codeowners/commands/ListCodeOwners.java#L95-L130

[nielsbasjes]

Fixed

[nielsbasjes]

And part of the 1.8.0 release