feat: compute thumbhash for images (#596)

* feat: compute thumbhash for images

Signed-off-by: newt <hi@newty.dev>

* Merge branch 'main' into feat/thumbhash

Signed-off-by: newt <hi@newty.dev>

* style: move comment onto newline

Signed-off-by: newt <hi@newty.dev>

* feat: make thumbhash optional

Signed-off-by: newt <hi@newty.dev>

---------

Signed-off-by: newt <hi@newty.dev>
Signed-off-by: newt (: <hi@newty.dev>
Signed-off-by: Tom <iamtomahawkx@gmail.com>
Co-authored-by: Tom <iamtomahawkx@gmail.com>

Cargo.lock

@@ -6824,6 +6824,7 @@ dependencies = [
  "simdutf8",
  "strum_macros",
  "tempfile",
+ "thumbhash",
  "tokio 1.49.0",
  "tower-http 0.5.2",
  "tracing",
@@ -8835,6 +8836,12 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "thumbhash"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b7726e0245a7331bd0c9a1fb4fd99fd695bcd478ca569f0eda2ff2cb14e7a00"
+
 [[package]]
 name = "tiff"
 version = "0.10.3"