Prepare Deno package

[yunchengyang515]

https://dev.to/brunnerlivio/create-your-first-module-with-deno-575k

Use postgres deno driver as example https://github.com/denodrivers/postgres for code structure

[yunchengyang515]

• Move all the package import to dep.ts

[yunchengyang515]

https://dev.to/reggi/organizing-files-in-a-deno-module-d63
follow this

[yunchengyang515]

Otherwise Deno's package is very flexible, should be good enough for v0.0.1, there is no hard requirements, mainly convetions I believe
cc. @jeffreyaven