egl: Add wrapper for EGLSync

[i509VCB]

• [x] Tested on all platforms changed
• [x] Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• [x] Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• [x] Created or updated an example program if it would help users understand this functionality

WIP:

• [x] Add way to create a Sync

[i509VCB]

Still need to write an example for sync and then one for import/export, but largely is done