Operator for StreamingSQL

[wagmarcel]

There is already an operator for submitting and monitoring jars. Next step is to implement an operator for Streaming SQL statements. To make sure that not every SQL statement needs a Flink task slot the new Statementset feature of Flink 1.13 is needed. Therefore an upgrade is needed to provide:

• Compatiblitiy with Flink 1.13 and Beam 2.27
• REST Gateway to submit Streaming SQL statements to Flink
• Backward compatibility with Flink 1.10 jars
• Kopf operator to enable Streaming SQL CRD management

[wagmarcel]

Some add ons are missing:

• Logger Lib for sql gateway
• BeamSQLTable indexer not working properly (linting conflict ...)