FTPConnector - new connector and documentation

[adrianfilip]

#Steps

• Add a new project
  -- Example: https://github.com/zio/zio-connect/blob/2507925dcd9acf5cb1dbb5e004afef3982ad6807/build.sbt#L38

• Create the following directory structure

     zio.connect.ftp
  

• Create the connector

   sealed trait FTPConnector
   
   case class LiveFTPConnector() extends FTPConnector { ... }
   
   object LiveFTPConnector {
       val layer: ZLayer[???, ???, FTPConnector] = {
           ...
           LiveFTPConnector()
       }
  
   }
  

• Provide accessors in the package object
  Example: https://github.com/zio/zio-connect/blob/master/connectors/file-connector/src/main/scala/zio/connect/file/package.scala

• Tests belong in the FTPConnectorSpec file.
  They use the accessors.
  Example:- https://github.com/zio/zio-connect/blob/master/connectors/file-connector/src/test/scala/zio/connect/file/FileConnectorSpec.scala

• There will be a LiveFTPConnectorSpec that runs the FTPConnectorSpec files for the LiveFTPConnector layer
  You could use the https://hub.docker.com/r/atmoz/sftp/ container with testcontainers.
  Example with testcontainers and Localstack S3 here - https://github.com/zio/zio-connect/pull/83/files#diff-e7e0899e455a741a644a05c0b26879d176a9126951477cd7c62dc19ade98b5cc

• Provide a TestFTPConnector layer that allows testing with a stub.
  Example - https://github.com/zio/zio-connect/blob/master/connectors/file-connector/src/main/scala/zio/connect/file/TestFileConnector.scala

[kevchuang]

I'm working on it