[Feature] Implement a simpler way to add Event signature to the Event indexing config.

[developeruche]

Motivation

What is to be achieved is, instead of adding an event signature as "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef" it should be added this way "Transfer(address,address,uint256)"