Beancount-dkb

- Emit `balance` directive for `Tagessaldo` entries in `ECImporter`
- Remove unused `ignore_tagessaldo` parameter from `CreditImporter`

- Fix metadata keys in CreditImporter

- Added CreditImporter to import CSV exports of Credit Cards

- Added ECImporter to import CSV exports of EC accounts


[Dr-Nuke]: https://github.com/Dr-Nuke
[bratekarate]: https://githun.com/bratekarate
[dmerkert]: https://github.com/dmerkert
[e11bits]: https://github.com/e11bits
[niels]: https://github.com/niels
[nils-werner]: https://github.com/nils-werner
[tbm]: https://github.com/tbm
[M4a1x]: https://github.com/M4a1x