Change User creation UI

[lennartploen]

To uniquely identify a user in the list of users (when you change the assignee for example), the "user name" needs to convey the following information:

1. Country (e.g. Ethiopia)
2. Organisation (e.g. Ministry of agriculture)
3. Role (eg project manager)
4. Project name

• "Country" is only necessary if it is decided to connect more than one partner country to the same donor node.
• "project" might be optional for the donor as one person can be responabile for all projects within a given country (e.g. VVK at KfW)

The list of users possibly selected will ever grow, as users can not be deleted. To avoid miss-spellings and facilitate selection of the right user in the list of users, ideally the UI for user creation allows these fields (country, organisation, role, project), and constructs both the "user name" and the login automatically from here. This also avoids the risk of entering personal data that must not be registered on the blockchain.