Update Open Source Support language

Please refer to updated text for DHF, included below as point of reference. Key changes are to say "made available under...", reference "Technical Support Handbook". Italicized portion is specific to DHF. The rest should be pretty boilerplate/straight copy paste.

The MarkLogic Data Hub Framework is maintained by MarkLogic Engineering and is made available under the Apache License 2.0. The Data Hub Framework core Java libraries and gradle commands are supported software for production use with MarkLogic Server. The QuickStart UI is designed for use in a development environment and is not currently supported for production use. Everyone is encouraged to file bug reports, feature requests, and pull requests through GitHub. This input is critical and will be carefully considered. However, we can’t promise a specific resolution or timeframe for any request. In addition, MarkLogic provides technical support for release tags of the MarkLogic Data Hub Framework to licensed customers under the terms outlined in the MarkLogic Technical Support Handbook. Customers with an active maintenance contract can sign up for MarkLogic Technical Support at https://help.marklogic.com/marklogic/AccountRequest.

The issue provides replacement support language but does not name the file containing the current text. Locate the existing Open Source Support section, replace it with the supplied wording and links, and verify that the documentation renders correctly.