HAProxy monitoring: Show HAProxy type services in PMM Inventory

When we'll dd new agent/service  types (haproxy) we need to reflect this properly in the Inventory page

In Addition, we need to add some protection to this bug (PMM-6903, PMM-6055 )

Acceptance criteria:

• Service and agents of HAProxy properly presented in inventory, not empty strings.
  names: TBD
• If the agent/service type is NOT having a Humanized name - we should try to present the technical type and humanize it (first symbol - caps, "_" or "-"  - spaces )