New Subbiomes for 1.19

Early 1.18 terrain generation had an issue where miniature biomes could be generated in extremely out of place locations. However, if implemented deliberately, I think this could provide more variety to existing biomes in the Wild Update. 

'Clearings,' small areas of meadow within large forests.

'Glades' small areas of oak forest surrounded by prairie, or small sections of snowy taiga surrounded by tundra.

'Oases,' small sections of Jungle Edge that generate around lakes and rivers in arid areas.

'Arbors' small sections of larger trees in normal forests. (Tall birch trees in normal birch forests, balloon oaks in normal oak forests, really big mushroom/dark oak trees in covered forests, etc.)