Improve Javadoc

[bchapuis]

The state of the javadoc can be improved. This issue is used to track progress.

Current status:

• [x] baremaps-blob
• [x] baremaps-blob-s3
• [ ] baremaps-cli
• [x] baremaps-osm
• [x] baremaps-osm-lmdb
• [x] baremaps-osm-postgres
• [x] baremaps-osm-rocksdb
• [x] baremaps-postgres
• [ ] baremaps-server-common
• [ ] baremaps-server-editor
• [ ] baremaps-server-studio
• [ ] baremaps-server-viewer
• [ ] baremaps-server-ogcapi
• [x] baremaps-stream
• [x] baremaps-tile
• [x] baremaps-tile-mbtiles
• [x] baremaps-tile-postgres

Continuous integration:

• [x] Make build fail when the javadoc contains errors
• [ ] Make build fail when the javadoc contains warnings