Change Felix default instructions globally

[mkjensen]

It would be helpful if the default instructions for Felix could be overwritten globally.

E.g. instead of having to include the following for each artifact, it would just need to be specified once.

<transitive>false</transitive>
<instructions>
  <DynamicImport-Package>*</DynamicImport-Package>
  <Import-Package>;</Import-Package>
</instructions>