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

從 assets/thumbnails/thumbnail_template.odg 開始，並將其與目前的網站主題進行比較，尤其是 Announcements 區段。檢視現有的影片範本和靜態 workbook 圖片，接著使用更新後的 logo、teal 色彩和 PT Sans 定義一致的設計處理方式。選定的範本樣式套用至影片和 workbook 圖片，並已與團隊一同檢閱後，即視為完成。