Add encoding option for CSV, JSON Data node configuration

[trgiangdo]

What would that feature address

For now, there is no way for the user to manipulate the encoding when reading a file of a CSV and JSON DataNode.

Pandas and (almost) all excel-related libraries do not support explicit encoding types for parquet and excel files, so it is not possible in the near future. Pickle Data node is not affected by the encoding, because Pickle is always binary file.

Description of the ideal solution The user should be able to configure

json_dn_cfg = Config.configure_json_data_node("dn_id", "path.json", encoding="utf-8")

and then, all reading/writing from the json_dn_cfg should use UTF-8 encoding.

TODO:

• [x] Implementation the feature.
• [x] Add read/write test cases.
• [x] Update the Configuration documentation of the User Manual.
• [x] Update the release notes.