ISIS-793: fix comment, make configuration of WebJars library easier to override
ISIS-793: make configuration of logging.properties easier to override.
ISIS-793: make registration of WebRequestCycleForIsis easier to override.
ISIS-793: make determination of DeploymentType easier to override.
ISIS-793: make easier to override the setup of CSS bundles
ISIS-793: just moving methods around in IsisWicketApplication (for config builder)

... already protected visibility so can be overridden if required.
ISIS-793: just moving methods around in IsisWicketApplication (for instantiating IsisWicketModule)

... already protected visibility so can be overridden if required.
ISIS-793: just moving methods around in IsisWicketApplication (CSS bundle)
ISIS-793: make easier to override filtering of Javascript contributions
ISIS-793: make easier to override mapping of page URLs
ISIS-793: just moving methods around in IsisWicketApplication (mountPage supporting method)
ISIS-793: make easier to override handling of runtime (metamodel) exceptions