Principles & Patterns project housekeeping

[russelltrow]

As the P&P projects haven't been active since early 2023 the Repos / Issues/ Discussions could do with a tidy.

Actions

• [x] Cleanup Principles Issues
• [x] Cleanup Principles Discussions
• [x] Cleanup Patterns Issues
• [x] Cleanup Patterns Discussions
• [x] Update the Manuals & Summaries