AUDIO: Added remaining brush entity sound effects

[Zungrysoft]

Description of Changes

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Adds all of the remaining brush entity sounds:

• buttons/airbut1.wav - Steam Metal button.
• doors/airdoor1.wav - Metal secret door move. (Old sound was moved to doors/basesec1.wav)
• doors/airdoor2.wav - Metal secret door stop. (Old sound was moved to doors/basesec2.wav)
• doors/doormv1.wav - Stone door move.
• doors/drclos4.wav - Stone door and medieval secret door stop.
• doors/latch2.wav - Medieval secret door start. (This is unused due to a bug in the progs.dat)
• doors/stndr1.wav - Stone Chain door move.
• doors/stndr2.wav - Stone Chain door stop.
• doors/winch2.wav - Medieval secret door move. (Modified the previous sound with new EQ and fixed looping.)
• misc/trigger1.wav - Large Switch trigger sound.
• plats/medplat1.wav - Chain Slow lift move.
• plats/medplat2.wav - Chain Slow lift stop.
• plats/train1.wav - Train move. (Duplicate of doors/winch2.wav)
• plats/train2.wav - Train stop.

Visual Sample

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https://github.com/user-attachments/assets/0dc9509e-085f-4e92-a5e2-c887c441e892

Checklist

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• [x] I have read the LibreQuake contribution guidelines
• [x] I have thoroughly tested my changes to the best of my ability
• [x] I confirm I have not contributed anything that would impact LibreQuake's licensing and usage
• [ ] This Pull Request fixes a critical issue that should be reviewed and merged as soon as possible