Fix water meter bubbles scaling with window

[Koopa1018]

Description of changes

Manually syncs the bubble systems' particle scale with the HUD's root. All three water particle systems share a process material, so the script only needs to get it from one of them.

Also, code refactor and cleanup, like usual.

Issue(s)

Closes #237.

Note

@sbritorodr also submitted a fix; see #242.

[jaschutte]

Looks good to me, a lot cleaner with getting rid of all those magic numbers.