[Feature](greenhouse-org-admin): Filtering for Plugin List

[uwe-mayer]

Description
We would like to add the possibility to filter the Plugin list within the greenhouse org-admin Area

Problem Statement
Currently we have an unsorted, unfilterable list of Plugins within the org-admin area. With increasing number of deployed plugins it becomes more and more unusable. E.g. I like to highlight clusterNames via the browser search to be able to focus on a set of Plugins

Proposed Solution
Add sorting and filtering options to the list.
Filter by:

• Plugin.Spec.ClusterName
• Plugin.Spec.PluginDefinition
• Plugin.Status.StatusConditions.Ready = true/false/unknown

Sort by:

• Plugin.Spec.DisplayName (default)
• Plugin.Spec.ClusterName then Plugin.Spec.DisplayName

Additional Context
The Plugin list screen is going to be replaced by a list/view only showing PluginPresets. So this should just be a quick solution. Maybe sorting is superflous if default sorting by displayName is implemented.