build: ignore macOS make deploy artefacts & add them to clean-local

.gitignore

@@ -132,3 +132,7 @@ db4/
 
 # clang-check
 *.plist
+
+osx_volname
+dist/
+*.background.tiff

Makefile.am

@@ -310,4 +310,5 @@ clean-docs:
 clean-local: clean-docs
 	rm -rf coverage_percent.txt test_bitcoin.coverage/ total.coverage/ test/tmp/ cache/ $(OSX_APP)
 	rm -rf test/functional/__pycache__ test/functional/test_framework/__pycache__ test/cache share/rpcauth/__pycache__
+	rm -rf osx_volname dist/ dpi36.background.tiff dpi72.background.tiff