[build] Sign '*.node' files for MacOS

[vrubezhny]

This PR has the goal to resolve issue #1403 by implementing the steps that are performed in Orbit to sign Mac '*.node' NPM modules for the WWD build.

[vrubezhny]

Mac signing breaks the WWD Jarsigner's signature as it changes and re-packs the already signed jar

[vrubezhny]

This time o.e.wwd plugin's jar appears to be correctly signed, however there is still some unsigned contents:

However I'm not sure if this is to be solved in WWD

[vrubezhny]

@jonahgraham Can you try building an EPP using the following PR's updated site: https://ci.eclipse.org/wildwebdeveloper/job/Wildwebdeveloper/job/PR-1404/6/artifact/repository/target/repository/ (or any later one if exists by the time)?

[mickaelistria]

This time o.e.wwd plugin's jar appears to be correctly signed, however there is still some unsigned contents:

Those are supposed to be signed by PGP, after the "assemble-repository" step.

[vrubezhny]

This time o.e.wwd plugin's jar appears to be correctly signed, however there is still some unsigned contents:

Those are supposed to be signed by PGP, after the "assemble-repository" step.

Then I expects we're OK with this (Just need to polish pom and remove not needed profile call added to Jenkinsfile)