write cloud_client and service/dataset modules (#8)

* WIP: create cloud_client and service/dataset packages

* add .DS_Store to .gitignore

* write aws cloud client and data storage client packages

data storage client is able to upload and download a file

* write service/data_storage module for a client to upload and download a file

calls the cloud_client

* write azure cloud client and data storage client packages

* rename root_client to root_provider in cloud_client/aws module

* write gcp cloud client and data storage client packages

* write upload dir function in service data storage module

* write ListObjects method for data storage clients for aws and azure

* implement list objects api as a pager

write pager methods for aws, azure, and gcp

* refactor UploadDir method for service/data_storage client

* write DownloadDir method for service/data_storage client

uses ListObjectsPager from the cloud_client/data_storage client

* rename service/data_storage to service/dataset module

* add List method to service/dataset client

* use DataStorageWhereUniqueInput instead of DataStorageContainerWhereUniqueInput in argument for service/dataset client methods

* refactor file creation in cloud_client/data_storage DownloadFile methods

just try to open the file

* refactor service/dataset methods

make structs public and clean up code

* fix file creation methods in DownloadDir method in cloud_client data_storage clients

* refactor and fix bugs in service/dataset module

* remove project relation query in DataStorageFragment

.gitignore

@@ -1,3 +1,5 @@
 .idea/
 schema.gql
 coverage.out
+
+.DS_Store