fix(ui): modify UI pipeline rules

Description

Modify UI pipeline rules:

• build CE image on each MR and after merging into master
• build UI- CE image on tag vX.X.X to be published to https://hub.docker.com/r/postgresai/ce-ui/
• build Platform image on tag ui/X.X.X (so the use of ui/ prefix becomes relevant only to Platform UI releases)

Related issue

Examples

Checklist

• MR description has been reviewed
• MR changes are functionally tested
• MR does NOT have API/CLI changes OR there are API/CLI changes and they have been reviewed & DOCS ARE ADJUSTED (reference doc, etc)
• MR does NOT have UI changes OR there are UI changes and they have been reviewed & UX IS REVIEWED