Upgrade Spring beans dependency to take advantage of mapped HTTPS XSD resources to embedded files

As discovered in NIFI-6439, the change for the Spring XSD dependencies from HTTP to HTTPS URLs blocks the application from running when disconnected from the internet. This is due to the plain HTTP URLs being mapped in an embedded properties file to embedded local XSD files, but the HTTPS URLs not being mapped.

As reported by patricker, as of May 2019, Spring had updated their mapping file to include the HTTPS URLs.

Once this upgrade is complete, the reversion of the URL protocols done in PR 3590 can be restored.