Slowly recover HP near statue

[gentlespoon]

Previously, HP recovery was only triggered once when the player enters the statue region.
The vanilla experience is that the player will slowly get HP from the statue as the statue regenerates its HP volume.
This PR is to match the experience.

(Also clean up the statue related files)

Type of changes

• Bug fix
• New feature
• Enhancement
• Documentation

Checklist:

• My code follows the style guidelines of this project
• My pull request is unique and no other pull requests have been opened for these changes
• I have read the Contributing note and Code of conduct
• I am responsible for any copyright issues with my code if it occurs in the future.