[Stale Content] Delete M-83-11 debt collection and privacy guidance — 40+ years old and superseded

## What needs to change
The summary file for OMB M-83-11 (Guidelines on the Relationship of the Debt Collection Act of 1982 to the Privacy Act of 1974, 1983) should be removed. This memo is over 40 years old and has been superseded by subsequent privacy guidance including OMB Circular A-108 (2016), which is already listed in the Guidance category.

## Where to find it
Navigate to `pages/_summaries/` and find the file linking to OMB M-83-11. Search if needed:
```
grep -r "M-83-11\|Debt Collection Act" pages/_summaries/
```

## Before deleting
Confirm nothing else in the repo links to this file:
```
grep -r "m-83-11" pages/
```

## How to verify
Visit https://resources.data.gov/categories/guidance and confirm the M-83-11 entry no longer appears.