Raw-rs: add post-processing steps (#1923)

* add convert_to_rgb step

* add code to generate gamma correction curve

* add gamma correction step

* fix clippy warnings and cargo fmt

* remove unnecessary dependencies

* Code review 1

* Code review 2

* fix the order of operations

* Code review 3

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Co-authored-by: Keavon Chambers <keavon@keavon.com>

libraries/raw-rs/Cargo.toml

@@ -13,7 +13,7 @@ repository = "https://github.com/GraphiteEditor/Graphite/tree/master/libraries/r
 documentation = "https://docs.rs/raw-rs"
 
 [features]
-raw-rs-tests = ["dep:image", "dep:libraw-rs", "dep:palette", "dep:reqwest"]
+raw-rs-tests = ["dep:image", "dep:libraw-rs", "dep:reqwest"]
 
 [dependencies]
 # Local dependencies
@@ -33,4 +33,3 @@ reqwest = { workspace = true, optional = true }
 
 # Optional dependencies (should be dev dependencies, but Cargo currently doesn't allow optional dev dependencies)
 libraw-rs = { version = "0.0.4", optional = true }
-palette = { version = "0.7.6", optional = true }