Add the possibility to ignore the Match directive

[iamFrancescoFerro]

This PR tries to make #6 less of an issue.

The go-git-v5 lib uses your nice ssh parser however in Alma 8/9 and most of RHEL there is this Match directive in the default ssh config and it completely breaks all the git operation in these OSes

While someone brave enough makes the implementation for parsing the Match I thought ignoring it would be enough.

Ideally we shouldn't be passing so many params to functions but I didn't want to refactor to much stuff.

After this PR is merged you could ignore the directive like this:

ssh_config.DefaultUserSettings.IgnoreMatchDirective = true

This

[quike]

@kevinburke could you take a look whenever you have a chance? thanks

[iamFrancescoFerro]

We can't even use the go mode replace because of this
https://github.com/src-d/go-git/blob/master/plumbing/transport/ssh/common.go#L23

we can't override

[oneirocosm]

I was just testing this out in my fork of the repo and found a bug. Line 431 of config.go also needs to check the ignoreMatchDirective flag.

[oneirocosm]

Found one more bug in this. The ignoreMatchDirective flag isn't getting persisted to included files.

To fix it, the newConfig function in config.go needs an ignoreMatchDirective bool parameter to propagate it to the returned &Config struct. That function only gets called once in parser.go, and the ignoreMatchDirective variable is already present to use as an argument.