Document query examples for aquarius/subgraph

[alexcos20]

Based on datawhale pdf, we should add query examples to our docs: https://discordapp.com/channels/612953348487905282/720631837122363412/896113759549018122

Maybe we can add more than that

[trentmc]

The ocean.py C2D readme points to a couple ddos too. Maybe helpful here.

• README: https://github.com/oceanprotocol/ocean.py/blob/main/READMEs/c2d-flow.md
• ALG_ddo: https://github.com/oceanprotocol/ocean.py/blob/main/READMEs/ALG_ddo.md
• DATA_ddo: https://github.com/oceanprotocol/ocean.py/blob/main/READMEs/DATA_ddo.md

[LoznianuAnamaria]

Now that we are porting to gitbook, we can either embed the postman examples @akshay-ap has created or add a sub-section with examples.