Add execution-order required/optional dependencies for data types

[ch4ika]

I've noticed that Health Syncing often can't set the lives correctly because the lives are set first, followed by the attributes. If the attributes are set first and then the health, it works correctly.

I only did a little debugging and didn't really get an overview.

This issue primarily concerns items that provide extra hearts. If the order of setting attributes and health is reversed, it works fine.

This problem is specifically related to health. If health syncing is enabled but the attributes are not loaded beforehand, the extra health is set to player.getMaxHealth instead of generic_max_health from the attributes.

[WiIIiam278]

I see, yeah - in essence this is down to the fact that sync data types can't currently depend on others. Not a major issue as in practice max health is usually kept relatively consistent between servers, but can become an issue.

Basically what needs to happen is that sync data types need a way of defining optional/required "dependencies" on other sync data types (by ID), and then for the plugin to correctly go through them in a suitable order. in this case we'd want to make attribute syncing depend on Health/Hunger & Potion Effect syncing first to prevent this sort of issue.

[WiIIiam278]

@ch4ika If you're able to compile the PR branch #309 and give it ago (in a test environment!), that'd be great. Otherwise, open a ticket on Discord / verify purchase, and I'll send you a build to try.