SSH access to Exasol database with other use accounts than "root"

[ckunki]

This can be relevant especially for external databases (outside Docker Container).

Priority:

• This ticket is optional and can be implemented in future if required

Acceptance criteria

• API, CLI and pytest_itde are enhanced to enable to specify the name of the account to use
• Entry in DatabaseInfo for Docker SSH user is constant root for other scenarios the entry needs to be dynamic