cherry-pick from hotfix

cleanup

choose smallest representation for media preview

ref #7056 Generate titleCache for newly created image galleries

ref #7056: add possibility to show preview of the image in media view

only remove not persisted media in deleteOperation

ref #6906 Fix Delete and move handler for media view

ref #6925 Inject context into operations to allow sync/async execution

Merge branch 'develop' into bulkEditorE4

Conflicts:¶

eu.etaxonomy.taxeditor.editor/META-INF/MANIFEST.MF¶

eu.etaxonomy.taxeditor.editor/src/main/java/eu/etaxonomy/taxeditor/editor/view/concept/e4/ConceptViewPartE4.java¶

eu.etaxonomy.taxeditor.editor/src/main/java/eu/etaxonomy/taxeditor/editor/view/descriptive/e4/FactualDataPartE4.java...¶

ref #6925 Pull up selection handler and service