docs: community docs for Repository creation and project donation

[Dule-martins]

Description I removed the Donate-a-project.md file and included the suggested example on how to donate an existing project and also how to start a new project under AsyncAPI

Here is a suggestion made by @derberg "this document can be removed and instead, in Getting-a-new-AsyncAPI-repository-approved.md file just add a note that https://github.com/orgs/asyncapi/discussions/223 is an example project that shows how donation of existing project looked like and https://github.com/orgs/asyncapi/discussions/300 is an example of new project started under AsyncAPI"

Related issue(s)

Resolves #903