Merge branch '#798' into dev

requirements.txt

res/i18n/ts/cs.ts

res/i18n/ts/de.ts

res/i18n/ts/es.ts

res/i18n/ts/fr.ts

res/i18n/ts/it.ts

res/i18n/ts/pl.ts

res/i18n/ts/pt.ts

res/i18n/ts/ru.ts

src/sakia/data/entities/source.py

src/sakia/data/entities/transaction.py

src/sakia/data/processors/dividends.py

src/sakia/data/processors/sources.py

src/sakia/data/processors/transactions.py

...data/repositories/006_add_sources_conditions_property.sql

...ia/data/repositories/007_add_sources_used_by_property.sql

src/sakia/data/repositories/meta.py

src/sakia/data/repositories/meta.sql

src/sakia/data/repositories/sources.py

src/sakia/data/repositories/transactions.py