Add Uuid v7 support?

[garak]

The PECL Uuid extension recently added the possibility of generating v7 uuids.
It would be nice to get it here too

[derrabus]

Sure. Do you want to work on it?

[garak]

Well, I'd love to, but I'm not quite sure I understand the logic behind the current implementation

[pavetheway91]

#539 might be of your interest. V6 and V7 are by all practical means, pretty much same thing with just a different epoch.