Lower required OpenGL version from 3.3 -> 3.0

[ts-korhonen]

Summary

These changes will drop the required OpenGL version from 3.3 to 3.0 on the OpenGL Core renderer. Shader default version is also dropped from 3.30 to 1.30 accordingly. This will hopefully allow older GPU's to work better with the renderer.

While dropping the version below 3.2 sync objects are not implemented by default. If ARB_sync extension is available, the functionality remains the same. Those with gpu/drivers that don't have sync objects will possibly experience a slow down in comparisson. This should not effect those users that we're able to use the renderer before.

Checklist

• Closes #xxx
• I have discussed this with core contributors already
• This pull request requires changes to the ROM set
  • I have opened a roms pull request - https://github.com/86Box/roms/pull/changeme/

References

Provide links to datasheets or other documentation that helped you implement this pull request.