File connections

All File (but not FileDF) connection classes (FTP, SFTP, HDFS and so on) requires specific Python clients to be installed.

Each client can be installed explicitly by passing connector name (in lowercase) to extras:

pip install onetl[ftp]  # specific connector
pip install onetl[ftp,ftps,sftp,hdfs,s3,webdav,samba]  # multiple connectors

To install all file connectors at once you can pass files to extras:

pip install onetl[files]

Otherwise class import will fail.