Bug 26403: Move credit and debit types into translatable YAML files

Bug 26403: Move credit and debit types into translatable YAML files

This patch moves account debit and credit types, as well as the CASH
payment type, into YAML files under
installer/data/en/mandatory. This should make the debit and credit types
translatable (for new installations only).

To test:
1. Apply patch
2. Update po files
   ./misc/translator/translate update xx-XX
3. View the xx-XX-installer.po file
   -->The default account debit and credit types (and cash payment type)
      should be available to be translated
4. Translate the strings
5. Apply the translations
   ./misc/translator/translate install xx-XX
6. Load the new translated YAML files (with a fresh install, or by deleting
   the values in the db and using ./misc/load_yaml.pl to load the files)
7. In the staff interface, go to Administration > Credit types
   --> They should be translated
8. Go to Administration > Debit types
   --> They should be translated

Signed-off-by: Magnus Enger <magnus@libriotech.no>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>