Enable pruning storage by size

[Alex6323]

Description of change

Enables pruning of the storage layer by specifying a target size.

Depends on #1397.

Links to any relevant issues

Type of change

• Enhancement (a non-breaking change which adds functionality)

How the change has been tested

Change checklist

• [x] I have followed the contribution guidelines for this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have checked that new and existing unit tests pass locally with my changes
• [x] I have updated the CHANGELOG.md, if my changes are significant enough