#5249 Add Fixed Grid Strategy

This is a request to add the new fixed grid strategy to the hummingbot codebase.

Snapshot vote where the HIP for this strategy was approved: https://snapshot.org/#/hbot-ip.eth/proposal/0xaf21d826282fcc0a4d77ad0fb775c37b7a5935af1ce106686065b4336de2f83f

Commonwealth discussion about this strategy: https://commonwealth.im/hummingbot-foundation/discussion/3763-fixed-grid-strategy-for-hummingbot

Medium article explaining and demonstrating the strategy: https://medium.com/@rkc2000/introducing-the-fixed-grid-strategy-for-hummingbot-d9b011c71e9b

Link to the pull request: https://github.com/hummingbot/hummingbot/pull/5249