Biome: Entity Spawning Panel: Search Bar & Clear Selected Button

The Entity Spawning Panel in the Biome mod element panel on the third page, lacks some features that should be there.

• A search bar for when selecting which entities to spawn. The search bar should for items in the list that contain the same letters not just the name from the beggining.
• A button to delete the selected entities from the list of chosen entities to spawn in that biome or just pressing the "delete" key to delete the selected items.