Upgrade Felix, OSGi and JRE. #56

[pavelhoral]

Dependency changes

• ✔ JRE version was upgraded to 1.8.
• ✔ Felix framework upgraded to 6.0.x.
• ❌ Left a lot of dependencies at their old versions (e.g. Gogo Shell). We should continue with the upgrade after this gets merged.

Implementation changes (OSGi specific)

• ✔ All Felix SCR Annotations were replaced with standard OSGi DS annotations.
• ✔ Previous implementation was using factory=true with suppressMetatypeWarning properties to generate empty OCD. Such construct is not possible with DS and I am not sure what purpose it had. Those properties were removed.
• ✔ Previous Felix SCR Maven plugin was automatically generating service.pid based on component name. This property is used on a lot of places in service lookup / filters. This approach is not possible with DS (see FELIX-5304). Service PID properties were removed where possible, however additional cleanup is still needed.

Bundle changes (metadata)

• ❌ Link to Creative Commons license disappeared from Bundle-License manifest attribute. This was not an intentional change, but it probably doesn't matter as CC-BY-NC was for docbook documentation.
• ✔ Newer build produces more exhaustive Import-Packages configuration. Seems to be in the direction of best-practices and should be ok.

Known (unrelated) issues

• Current master branch is broken due to JwtSessionModule and AbstractJwtSessionModule are incompatible when handling Max-Age cookie attribute wrensec-commons#22 (not caused by the upgrade).

[pavelhoral]

Seems like Semaphore is having some issues with the build (will need to investigate a bit). I know I will have to deal with PGP artifact signatures, but the project builds and runs fine on my computer.

[pavelhoral]

Every issue has been hopefully resolved. PR is ready to be merged (rebased & squashed).

[karelmaxa]

LGTM!