Add image examples

[bgins]

Description

This PR adds a set of image processing example functions including crop, rotate, blur, and grayscale.

Type of change

• New feature (non-breaking change that adds functionality)

Test plan (required)

Run cargo test -p homestar-guest-wasm and the processed images will be output to homestar-guest-wasm/out/. Not sure if out is the convention for an output directory in Rust. Let me know if we should use something else.

Screenshots/Screencaps

Original image:

Processed images:

[codecov]

Codecov Report

Merging #124 (ba920b1) into main (7ecf856) will decrease coverage by 1.10%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main     #124      +/-   ##
==========================================
- Coverage   42.40%   41.31%   -1.10%     
==========================================
  Files          28       28              
  Lines        1462     1462              
  Branches      369      388      +19     
==========================================
- Hits          620      604      -16     
  Misses        630      630              
- Partials      212      228      +16     

Impacted Files	Coverage Δ
homestar-runtime/src/network/swarm.rs	0.00% <0.00%> (ø)

... and 5 files with indirect coverage changes