[DOC] Create README template to be used for all `near` repos

[thisisjoshford]

[bucanero]

Proposed github repo template:

https://github.com/near-examples/readme-template

[bucanero]

@thisisjoshford @gagdiez, what do you think about this proposed README template?

[gagdiez]

LGTM for big projects (QueryAPI, DA, Indexer, etc), and for small examples on docs we can follow the convention we are using now, which is simpler since the repos are also simpler