Remove pyodbc docker file

[JCZuurmond]

Currently there is a docker file which installs the ODBC driver for Microsoft SQL server. The container created from the docker file is used in the Circle CI, only. This container/file is not needed if the ODBC driver is installed in a CircleCI (build) job.

• this docker file/container is redundant since we have circleci
• changing the docker container is cumbersome, since the publishing is not automated.
  The docker file also install the requirements.txt which is causing version problems and the requirements.txt does not exists if PR Clean up tox ini #105 is merged.

[JCZuurmond]

I think it would make sense to make a build stage like here