feat: add icon and description for Stable Diffusion benchmark

[anhappdev]

• The icon is drawn by me using Figma. We can replace it with one from a designer later.
• Please provide me a description for the Stable Diffusion benchmark (@Mostelk)

[github-actions[bot]]

MLCommons CLA bot All contributors have signed the MLCommons CLA ✍️ ✅

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[freedomtan]

@AhmedTElthakeb please report number of parameters and FLOPs of the 3 models we use.

[AhmedTElthakeb]

Model Name	Parameters	MACS
text_encoder	123060480	8.958 G
vae_decoder	49490199	1273.718 G
sd_diffusion_1	447042560	147.435 G
sd_diffusion_2	412478404	281.060 G

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[anhappdev]

@Mostelk Please provide a description for the Stable Diffusion benchmark.