Work with DataTable api

[ErnestK]

Hello,

I was found some api to work with data tables.
expert_sender_data_table_api

For my project I need methods "DataTablesAddMultipleRows" and "DataTablesClearTable".

I wrote code code which can work with that api.
I can create pr to merge it to you project.
@beorc what do you think?

[beorc]

I'm not an owner of this gem for now, it seems I'm not the right person to answer this question.

[kovalevsky]

@ErnestK sure, feel free to create the PR
/cc @zsand