implement synapse destination

[rudolfix]

Background
We'd like to add destination for Synapse. There's previous work done here:
#740

Our goals are:

1. support most common use case of loading data into synapse (is it copying PARQUET/JSON/CSV from azure storage into synapse)?
2. supporting insert-values would be nice (but not necessary AFAIK synapse can insert 1 record per query)
3. support all write dispositions (append, replace, merge)
4. reuse as much code from MSSQL destination by subclassing, extracting common base class etc. - whatever necessary
5. possibly supporting Azure specific authentication modes (again: following the most common use cases)