Review & Verify OSGi Support in Tamaya

Need to verify that Tamaya works in OSGi environments.

The test TestConfigIntegration was used to verify this in the past, but stopped working and was ignored. Its an indication that OSGi support doesn't work too completely.

Functionality Outline:
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• Tamaya should load in an OSGI environment correctly. The SE API should work OOTB. This is achieved by loading an alternate ServiceContext implementation, when OSGI is detected (part of the core module). The implementation does explore the bundle for registered ServiceLoader files and registers them as according OSGI services. On the other hand the ServiceContext is retrieving services using the OSGI Service mechanism, ignoring the standard ServiceLoader mechanism (that does not work).
• OSGI services can be leveraged by configuring properties with the Tamaya injection API. Hereby evaluation of the values is performed using the OSGI ConfigAdmin service.
• As third building block Tamaya registers its own ConfigAdmin implementation, with higher priority than the standard one. Tamaya's priority as well if its overriding, or extending the default ConfigAdmin service, is configurable using system properties.

So given we have the first bullet point working, I will definitively also will help writing further tests for these features The basic mechanism I saw working, hopefully there will no bigger surprise...