[BUG] Update DEVELOPMENT.md and CONTRIBUTING.md after repo split

[kronosapiens]

After pulling out Katana and Torii into separate repositories, the DEVELOPMENT and CONTRIBUTING guides seems to be out-of-date. This may make it difficult for newer developers to begin contributing to the project. We should review these docs and make sure they are up-to-date.

[ritik4ever]

can i take this issue