Extend integration tests to test conversion of all common formats we claim to support.

Extend integration tests that acually start Tika (fallback and server) and convert actual documents to test conversion of all common formats we claim to support.

Namely:

- `*.docx`
- `*.doc`
- `*.xlsx`
- `*.xls`
- `*.pptx`
- `*.ppt`
- `*.rtf`
- `*.odt`
- `*.swx`
- `*.pdf`
- `*.eml`
- `*.`

All assets are the simplest possible document in the respective format, a document containing just "Lorem Ipsum".