Move parsing functions to pkg/parsers and the specific kernel handling

functions to pkg/parsers/kernel, and parsing filters to
pkg/parsers/filter. Adjust imports and package references.

Docker-DCO-1.1-Signed-off-by: Erik Hollensbe <github@hollensbe.org> (github: erikh)

parsers/kernel/uname_linux.go

@@ -0,0 +1,18 @@
+// +build amd64
+
+package kernel
+
+import (
+	"syscall"
+)
+
+type Utsname syscall.Utsname
+
+func uname() (*syscall.Utsname, error) {
+	uts := &syscall.Utsname{}
+
+	if err := syscall.Uname(uts); err != nil {
+		return nil, err
+	}
+	return uts, nil
+}