[WIP][FEATURE] added possibility to convert account types

added configuration

__Tasks:__
- [ ] integration in ui
- [ ] api adjustments
- [ ] test coverage
- [ ] gather feedback for my changes

__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | yes
| Fixed tickets | none
| Doc           | none