- Update screenshots and videos with better quality

- Remove the header in the videos
- Remove video controls in the thumbnails

src/main/webapp/app/course/competencies/components/course-competency-explanation-modal/course-competency-explanation-modal.component.html

@@ -24,7 +24,7 @@ <h5 jhiTranslate="artemisApp.courseCompetency.featureExplanation.courseCompetenc
             <p jhiTranslate="artemisApp.courseCompetency.featureExplanation.courseCompetencyCreation.paragraph3"></p>
             <p jhiTranslate="artemisApp.courseCompetency.featureExplanation.courseCompetencyCreation.paragraph4"></p>
             <div class="explanation-model-gif">
-                <video controls preload="metadata" aria-label="Tutorial: Creating course competencies" poster="public/videos/course-competencies/create-competencies-poster.png">
+                <video controls preload="metadata" aria-label="Tutorial: Creating course competencies" poster="public/videos/course-competencies/create-competencies-poster.jpg">
                     <source src="public/videos/course-competencies/create-competencies.mp4" type="video/mp4" />
                     <p jhiTranslate="artemisApp.courseCompetency.featureExplanation.courseCompetencyRelations.relationVideoParagraph.first"></p>
                     <a href="public/videos/course-competencies/create-competencies.mp4"
@@ -48,7 +48,7 @@ <h5 jhiTranslate="artemisApp.courseCompetency.featureExplanation.courseCompetenc
                     controls
                     preload="metadata"
                     aria-label="Tutorial: Creating course competency relations"
-                    poster="public/videos/course-competencies/create-course-competency-relations-poster.png"
+                    poster="public/videos/course-competencies/create-course-competency-relations-poster.jpg"
                 >
                     <source src="public/videos/course-competencies/create-course-competency-relations.mp4" type="video/mp4" />
                     <p jhiTranslate="artemisApp.courseCompetency.featureExplanation.courseCompetencyRelations.relationVideoParagraph.first"></p>