Feature request: Allow to change icons for services using custom connectors.

[fuzmish]

Is your feature request related to a problem? Please describe.
We have several services using custom connectors. For example, there are three custom dashboard services:

They have a common icon, which causes visibility problems in the data explorer.
In general, the icon for services that use custom connectors is fixed, but it would be nice to be able to change this. 👍

Describe the solution you'd like

• (Prefer) Allow users to upload any image from the UI in the service settings to change the icon.
• (And/Or) Add a mechanism to embed image resources in the custom connector implementation.

Describe alternatives you've considered
According to the UI code, this icon is hard-coded and there seems to be no workaround.

Additional context
None