feat: create a graph dataset hub

[wey-gu]

to enable polished dataset being shared and loaded with ease.

[wey-gu]

• [ ] https://github.com/wey-gu/supplychain-dataset-gen/tree/main/data_sample
• [ ] https://github.com/wey-gu/movie-recommendation-dataset
• [ ] https://github.com/wey-gu/nebula-shareholding-example
• [ ] https://github.com/wey-gu/covid-track-graph-datagen
• [ ] https://github.com/wey-gu/identity-correlation-datagen/tree/main/sample/hand_crafted

more from https://github.com/vesoft-inc/nebula-docs-cn/issues/1388

[wey-gu]

created on https://github.com/wey-gu/awesome-graph-dataset , will do integration with it.

[wey-gu]

done within https://graph-hub.siwei.io/