[leo_gateway][cowboy] Upgrade Ninenines/Cowboy to 2.4.0

[mocchira]

The following procedures will be needed to achieve the goal.

TODO

• [ ] Refactor the code in leo_gateway based on Cowboy v1.0 To v2.0
• [ ] Refactor the code in leo_gateway based on Cowboy v2.0 To v2.1
• [ ] Refactor the code in leo_gateway based on Cowboy v2.1 To v2.2
• [ ] Refactor the code in leo_gateway based on Cowboy v2.3 To v2.2
• [ ] Refactor the code in leo_gateway based on Cowboy v2.3 To v2.4
• [ ] Folk cowboy and apply some patches including in LeoProject/Cowboy branch to deal with some S3-Clients that don't conform HTTP spec

Note

This task should be done before getting #1006 started in order to avoid the cowboy version conflict.

[mocchira]

Note: At first, check the latest cowboy version when you get started this issue.