mlange-42/arche: Arche v0.8.0

Entity relations were added as a first-class feature (#231, #271)

Relations are used to represent graphs of entities, e.g. hierarchies. They can be added, removed and queried just like normal components. The new feature offers ergonomic handling of entity relations, and provides relation queries with native performance.

• Removed World.Batch for entity batch creation, use Builder instead (#239)
• Rework of generic entity creation API, use MapX.New, MapX.NewWith, MapX.NewBatch and MapX.NewQuery (#239, #252)
• Stats object WorldStats etc. adapted for new structure of archetypes nested in nodes (#258)
• Removed generic filter method FilterX.Filter (#271)
• Method Batch.NewQuery renamed to Batch.NewBatchQ (#298)

• Relation archetypes are removed when they are empty and the target entity is dead (#238, #242)
• Support an unlimited number of cached filters, instead of 128 (#245)
• WorldStats contains the number of cached filters (#247)
• Archetypes with entity relations are removed on World.Reset (#247)
• Capacity increment can be configured separately for relation archetypes (#257)
• Adds methods for faster, unchecked entity relation access (#259)
• Re-introduce World.Batch for batch-processing of entities (add/remove/exchange) (#264)
• New method Builder.Add for adding components with a target to entities (#264)
• New method Batch.SetRelation for batch-setting entity relations (#265)
• New methods Builder.AddQ, Builder.RemoveQ etc. to get a query over batch-processed entities (#297)
• Sends an EntityEvent to the world listener on relation target changes (#265)

• Reduce memory footprint of archetypes by moving properties to nodes (#237)
• Queries iterate archetype graph nodes in an outer loop, potentially skipping nested relation archetypes (#248)
• Relation archetypes are recycled in archetype graph nodes (#248)
• Already empty archetypes are not zeroed on reset (#248)
• Optimize RelationFilter: get archetype directly instead of iterating complete node (#251)
• Cached filters use swap-remove when removing an archetype (#253)
• Speed up generic query re-compilation after changing the relation target (#255)
• Speed up archetype and node iteration to be as fast as before the new nested structure (#270, #288)
• Filter cache stores archetype graph nodes instead of archetypes (#276) (#288)
• Use uint32 instead of uintptr for indices and query iteration counter (#283)
• Cached filters use a map for faster removal of archetypes (#289)
• Speed up iterating through many archetypes by approx. 10% (#301)

• Adds an example for creating and querying entity relations (#256)
• Adds a section on entity relations to the ARCHITECTURE.md document (#256)
• Replace Aos benchmarks plot in README for pointer iteration fix #284 (#285)
• Adds a plot for entity relation benchmarks to ARCHITECTURE.md (#290)
• Adds an outline of the most important types and functions to each sub-package (#295)

• Remove go-gameengine-ecs from Arche benchmarks (but not from competition!) (#228)
• Reduce memory size of Query and internal archetype list by 8 bytes (#230)
• Generic filters are locked when registered for caching (#241)
• Adds benchmarks for getting and setting entity relations (#259)
• Arche now has an official logo (#273)
• Use for loop with counter in AoS competition benchmarks, to allow for pointers (#284)