decomp: add a bunch of enemy files (#2101)

Adds the following files:

- `amphibian`
- `centurion`
- `ginsu`
- `grenadier`
- `hopper`
- `metalmonk`
- `monster-frog`
- `predator-graph`
- `predator-h`
- `predator`
- `rapid-gunner`
- `rhino`
- `rhino-wall`
- `tomb-baby-spider`

Also adds the DGOs for the following levels:

- Mar's Tomb
- Mountain Temple
- Drill Platform
- Sacred Site (Sage Hut)

Manual patches:

- The decompiler emits `(b! #t cfg-17)` in `(trans hostile hopper)`
without putting a `(label cfg-17)` anywhere
- Added cast to `art-joint-anim` in `(code broken rhino-wall)` and
`(code hit rhino-wall)`

Other notes:

- `amphibian` seems to occasionally crash when using its tongue attack.
Haven't investigated this yet
- `ginsu` crashes after being killed somewhere in the `deactivate`
method, possibly because of its `part-spawner`
- Predators aren't spawning in the forest hunt mission, not sure if
`forest-obs` might be needed for that or if it's something else
- The `rhino-wall` STR animation seems to load (albeit a bit broken due
to missing VAG stream playback), but causes the viewport to shrink as
soon as it's played
- I added `pegasus::74` to the `event_handler_hack` bool in
`variable_naming.cpp` because I got a `none` cast after changing the
return value of `enemy::74`

test/decompiler/reference/jak2/engine/spatial-hash/spatial-hash-h_REF.gc

@@ -155,7 +155,7 @@
     (update-from-spheres (_type_) none 28)
     (sphere-hash-method-29 (_type_ find-nav-sphere-ids-params int int int) none 29)
     (find-nav-sphere-ids (_type_ find-nav-sphere-ids-params) none 30)
-    (add-sphere-with-mask-and-id (_type_ vector int int) none 31)
+    (add-sphere-with-mask-and-id (_type_ vector int int) symbol 31)
     (sphere-hash-method-32 (_type_ vector vector float int) symbol 32)
     (remove-by-id (_type_ sphere int) none 33)
     )