Add API Key functionality

[igeligel]

For public projects it might be cool to have an API Interface.

• Create masterkey field in configuration
• Create API endpoint to add/delete API Keys with masterkey
• API Key is needed for inventory request
• Small Database for API Key save

configuration:

{
  "...",
  apiKeys: {
    enabled: true,
    masterkey: 'dadasdwdawdasdaw'
  }
}