Resolve "Allow to disable data manager load method via keyword argument"

This MR adds the enabled keyword argument to the DataManager.load method such that it is possible to disable a load entry from within a recursively updated configuration hierarchy.

This behaviour is then equivalent to the behaviour in PlotManager.plot.

Anything to double-check?

Nope.

Can this MR be accepted?

• Implemented the changes
• Tests added or adjusted
• Checked code coverage on new and adjusted code
• Pipeline passes
• Changelog entry added
• Approved by @daniellake

This is then to be 🍒 ⛏ ed into release/v0.11 and get version 0.11.2!

Related issues

Closes #127 (closed)