Add analysis code

Start of reorganization of the repository to contain all of the analysis code. Now consists of four components:

• pbv3 module to parse, calibrate and convert the test results
• tools collection of helpful tools to manipulate and visualize test results
• webreport generation of a web reporting using results from the ITk production database
• studies a series of local dedicated studies

The most useful part here is the pbv3.tests module. It makes it easy to get access to calibrated (and converted) test results. It does have some assumption on column names in the test results, which should already be consistent in powertools. An example of the usage can be seen in pbv3_plot_monitor.