Plugin dev: improve resource handling

There are different kinds of resources. Not all are supported well by the platform at the moment (and require manual per-app pom.xml configuration):

	Resource	Path	Remarks
[x]	Resources the platform needs at runtime (server-side), not published to web	/resources	Example: plugin.properties, migrations/
[x]	Resources generated at build-time (through Webpack) and are published to web	/resources/web
[x]	Static resources (which do not go through Webpack, and are) published to web	/resources-static	proposed behavior: copy to /resources/web once build is complete
[x]	Resources needed at build-time: goes through Webpack, output goes to /resources/web	/resources-build	proposed

@mukil FYI