Move bazel.Properties to a BazelModuleBase

This allows more direct access to the bazel label and whether the module
is bp2build available.

Test: go test *
Change-Id: I23375835d20fa53d7d94127b2dc2d5bb20487bfb
diff --git a/cc/library_headers.go b/cc/library_headers.go
index e5a5557..5b61832 100644
--- a/cc/library_headers.go
+++ b/cc/library_headers.go
@@ -86,7 +86,7 @@
 		return
 	}
 
-	if !module.Properties.Bazel_module.Bp2build_available {
+	if !module.ConvertWithBp2build() {
 		return
 	}