Use server name as narrative text in CapabilityStatement

[subigre]

It may be the expected behavior as name, version, copyright, etc. are all customizable but in my case, I would like to have my server name as narrative text of the CapabilityStatement.

Changelog:

• Use configuration.getServerName() as value for the narrative text generated by ServerCapabilityStatementProvider class
• Unit test

If this is the expected behavior, discard the PR