MLPro-OA: Preparation and design updates

This release prepares the upcoming sub-framework MLPro-OA for online machine learning. It doesn't yet provide new functionalities or significant bugfixes. It rather ensures compatibility with MLPro-Int-River and MLPro-Int-scikit-learn on an updated design level.

What's Changed

MLPro-SL - Supervised Learning

• SL: Initial Design by @laxmikantbaheti in #772

MLPro-OA - Online Adaptivity

• OA: Cluster Analysis by @detlefarend in #953
• OA: General systematics for cluster properties #944 by @detlefarend in #957
• OA: Maintenance of Howtos for OA-Streams by @detlefarend in #960
• OA: Templates for Cluster Analyzers #589 by @detlefarend in #958

MLPro-BF - Basic Functions

• BF-Model: Hyperparameter Updates through Event Handling by @laxmikantbaheti in #787
• Refact: Parameter p_outlier_frequency of Class StreamMLProPOutliers s… by @detlefarend in #949
• BF: General systematics for properties (and their derivatives) #943 by @detlefarend in #950
• Refact: Class bf.math.geometry.Point - Replace parent bf.math.Element… by @detlefarend in #955
• Refact: Class bf.math.geometry.Point - Replace parent bf.math.Element(2) by @detlefarend in #956

Full Changelog: v1.4.0...v1.4.1