Bug 566638 - Make linux proxy support work for all archs

- add new o.e.core.net.linux fragment that is implemented using
  JNA and can support multiple architectures
- make o.e.core.net.linux.x86_64 an empty fragment that requires
  new o.e.core.net.linux
- remove UnixProxyProvider as it is no longer used

Change-Id: I612371fa1d664f2b312eefb1554d599ff583d44b
Signed-off-by: Jeff Johnston <jjohnstn@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.team/+/175195
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>
17 files changed