Encryption support.

Summary

This release contains a major refactoring of the C++ layer. This also includes the removal of several C functions, which were exposed to the R-layer, but effectively unused. Also, r-exasol now supports encryption of the data channel via TLS.

Features / Enhancements

#63 Refactor C layer
#56:Created SSL Socket

Bug Fixes

#71 Fixed docker image nightly upload
#78: Fixed cpp and windows/mac build on GHA (#80)
#73: Added debug log

Compile Dependency Updates

#OpenSSL

Linux

n/a

####Windows
n/a

Runtime Dependency Updates

n/a

Test Dependency Updates

n/a