Implement filter shaders

[amylizzle]

https://www.byond.com/docs/ref/#/{notes}/filters

Each of these needs a shader and making sure parameters are set appropriately in OpenDreamClient/Rendering/ClientAppearanceSystem.cs

To add a shader, add the SWSL file to Resources/Shaders/ and set the metadata in Resources/Prototypes/Shaders/dreamshaders.yml

• [x] alpha (#1043)
• [ ] angular blur
• [ ] bloom
• [X] color matrix (#1062)
• [x] displacement map (#1243)
• [x] drop shadow (#1180)
• [x] gaussian blur (#798)
• [ ] layering
• [ ] motion blur
• [x] outline (#798)
• [ ] radial blur
• [ ] rays
• [ ] ripple
• [ ] wave

See #798 for details