Add QueryBuilder, generalize filtering in get_corpus().

[carschno]

Initial design for more generalizable filtering with initial implementation:

• Add weaviate.QueryBuilder class
• Generalize query filters in WeviateDatabaseManager.get_corpus() class
• Make specific fields for year filters explicit

[sonarcloud[bot]]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
92.3% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud