[DOCS] Add documentation pages for plugins available in the docs directory

[Manar-Elhabbal7]

Description

While exploring the WasmEdge documentation, I noticed that some plugins available in the plugins/ directory do not have corresponding documentation pages

This makes it harder for users to discover and understand available plugins without looking through the source code.

It would be helpful to add documentation for the plugins

Screenshots

No response

Additional information

Plugins available :

• wasi_crypto
• wasi_http
• wasi_nn
• wasi_poll
• wasm_bpf
• wasmedge_ffmpeg
• wasmedge_image
• wasmedge_ocr
• wasmedge_opencvmini
• wasmedge_process
• wasmedge_stablediffusion
• wasmedge_tensorflow
• wasmedge_tensorflowlite
• wasmedge_zlib