[web] Admin Settings > Users: Show loading indicator for filter and search

[tbsbdr]

Description

relates to https://github.com/owncloud/enterprise/issues/6597

User Stories

• As an Admin I want to know if the system is loading, so that I know if I should wait.

Value

• visibility of system status
• avoid human error

Acceptance Criteria

• Show loading indicator if the user needs to wait after having applied a filter
• Show loading indicator if the user needs to wait after having conducted a search
• Ideally show the indicator only, if the loading takes longer than ~ 1 second / debounce

Definition of ready

• Everybody needs to understand the value written in the user story
• Acceptance criteria have to be defined
• All dependencies of the user story need to be identified
• Feature should be seen from an end user perspective
• Story has to be estimated
• Story points need to be less than 20

Definition of done

• Functional requirements
  • Functionality described in the user story works
  • Acceptance criteria are fulfilled
• Quality
  • Code review happened
  • CI is green (that includes new and existing automated tests)
  • Critical code received unit tests by the developer
• Non-functional requirements
  • No sonar cloud issues