Added a module for loading qudi data as pandas DataFrame in a notebook

[alrik-durand]

Description

I've added a module with functions useful for loading a qudi .dat file.
They can extract parameters, column keys an data.
Also this module can be used to create a pandas DataFrame from one or multiple data files.

I've added this module in tools/data_analysis, I wasn't sure were would be the best location.

Motivation and Context

This PR follows the mail exchange "[qudi-dev] Managing saved measurement data".
One point was that qudi does not provide any tool for data anlysis once they are saved. This is understandable as Qudi focus mainly on the acquisition, not the post analysis.
But a lack of such tools force the users to develop their own tools, often re-inventing the wheel, for basic data loading.
To answer that need, I propose to add some tools for the most basic operations. The first tool here is solely the functions needed to import one or multiple data files in different ways.

How Has This Been Tested?

We have used a similar code for quite some time, but because of this PR I rewrote most of it. I tested it with real data to check that everything was still working.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• I have documented my changes in the changelog (documentation/changelog.md)
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added/updated for the module the config example in the docstring of the class accordingly.
• I have checked that the change does not contain obvious errors (syntax, indentation, mutable default values).
• I have tested my changes using 'Load all modules' on the default dummy configuration with my changes included.
• All changed Jupyter notebooks have been stripped of their output cells.