[Maps] Advertise on-prem option

[thomasneirynck]

Describe the feature:

When on-prem EMS is available, a user should be notified on how this can be used. This is similar to how Gold+ only functionality is now advertised in the UX.

Describe a specific use case for the feature:

When a user does a local deployment of Kibana, in Maps they should see in the EMS-card that on-prem EMS is available.

When on-prem is setup, the user should understand they are connecting to on-prem resources.

[elasticmachine]

Pinging @elastic/kibana-gis (Team:Geo)

[jsanz]

@thomasneirynck should this option also alert users that Coordinate and Region visualizations won't work against EMS basemaps?

[thomasneirynck]

@jsanz sorry for the delayed response. yes, we would need to introduce some wording or messaging in the legacy visualizations that on-prem does not work for these. That can be part of the PR to close this issue.

[thomasneirynck]

After discussion, these are the UX tweaks:

• Advertise self-hosted if app cannot connect to EMS (regardless of license level), in wizard-card
• Do not advertise if EMS is functioning with enterprise license
• Change wording if users have self-hosted deployment (basemap/boundaries. In wizard-card and source-details)
• Change error message for self hosted deployment (baseman/boundaries. In wizard-card and layer-details).