Allow compressed catalog.txt
Allow compressed catalog.txt

bookworm prep preDatabaseMetadata now supports a --gzip flag, for large
datasets. Since other processes a dependent on 'catalog.txt', this is
only useful with a manual named pipe; e.g.

```
mkfifo .bookworm/metadata/catalog.txt
gunzip -c .bookworm/metadata/catalog.txt.gz > .bookworm/metadata/catalog.txt &
```

This commit also allows a gzipped jsoncatalog_derived.txt.

Bookworm-project/BookwormDB,Bookworm-project/BookwormDB