Datatracer

* Add new `update_metadata` endpoint to the REST API.
* New demo dataset and new tutorial.

* Add initial version of pretrained solvers
* Reorganize ColumnMapSolver code tree
* Add REST API to access DataTracer solvers via HTTP

* Finish Column Mapping and add tutorial
* Minor refactoring and adding docstrings
* Fix testing config

* Curate configuration and dependencies

First release.

Features:

* Primary Key Detection
* Foreign Key Detection
* Column Mapping