Update Video Templates To Match Website Theme

The templates shown in the beginning of each video in the Learning Path used to match the general theme of the InnerSource Commons website. The website got a fresh new look at some point, but, the video templates have not.

The website's new theme uses teal (#0CA7A7) as the main action color and PT Sans as the font. The logo has also been refreshed to have a smaller outer border.

At a bare minimum, it would be great if the existing templates could use the new logo, colors, and fonts. If we're feeling slightly more adventurous, we could go for a look that matches overlays found in other areas of the website (see the Announcements section for an example). And if we're feeling really ambitious we could design something totally new and unique and use that.

It's totally up to whoever takes up this issue how they want to go about solving it, so long as they collaborate with the group as they go.

Keep in mind that any template we use will also need to be applied to the static images we use for workbooks (or some variation of it at least).

@lenucksi pointed out the original templates, created by @RJPlog, are located here:
https://github.com/InnerSourceCommons/InnerSourceLearningPath/blob/main/assets/thumbnails/thumbnail_template.odg

assets/thumbnails/thumbnail_template.odg から始め、現在の Web サイトのテーマ、特に Announcements セクションと比較します。既存の動画テンプレートと静的な workbook 画像を確認し、更新されたロゴ、teal カラー、PT Sans を使用した一貫したデザインを定義します。選択したテンプレートスタイルが動画と workbook 画像の両方に適用され、グループでレビューされれば完了です。