Remove `credentials` from state file

[daniel-mader]

Description

Credentials should only persisted in the Stronghold file and removed from the state entirely. References to the credentials themselves can still be left in the state (such as ids).

Motivation

No response

Resources

No response

To-do List

• Remove credentials data from the state.json file (references can be left in)
• Only in local development: log credentials to a separate file