Quadlet build - add support for IgnoreFile key

Resolves: https://github.com/containers/podman/issues/27268

Signed-off-by: Ygal Blum <ygal.blum@gmail.com>

test/e2e/quadlet/ignorefile.build

@@ -0,0 +1,6 @@
+## assert-podman-args "--ignorefile" "/path/to/.customignore"
+
+[Build]
+ImageTag=localhost/imagename
+SetWorkingDirectory=unit
+IgnoreFile=/path/to/.customignore

test/e2e/quadlet_test.go

@@ -1056,6 +1056,7 @@ BOGUS=foo
 		Entry("Build - ForceRM Key", "force-rm.build"),
 		Entry("Build - GlobalArgs", "globalargs.build"),
 		Entry("Build - GroupAdd Key", "group-add.build"),
+		Entry("Build - IgnoreFile Key", "ignorefile.build"),
 		Entry("Build - Containers Conf Modules", "containersconfmodule.build"),
 		Entry("Build - Label Key", "label.build"),
 		Entry("Build - Multiple Tags", "multiple-tags.build"),