RPMDB parsing can fatally stop cataloging

Derived from https://github.com/anchore/grype/issues/525 , syft errors out on analysis when an RPMDB cannot be parsed:
```
✔ Vulnerability DB [no update available]
New version of grype is available: 0.27.0
✔ Parsed image
⠏ Cataloging packages [packages 0]
1 error occurred:
* failed to catalog: 1 error occurred:
* unable to catalog rpmdb package=/var/lib/rpm/Packages: unexpected page size: 1048576
```

A few observations:
1) this should not be a fatal error
2) we can fix this in go-rpmdb to account for unexpected sizes (possibly)
3) there is no steps to reproduce at this time

Start by tracing Syft's RPMDB cataloging path into go-rpmdb and inspect how unexpected page sizes are handled. Establish a reproduction for the reported /var/lib/rpm/Packages failure, then verify that an unparseable RPMDB no longer fatally stops cataloging.

Written by the indexing model from the issue text.