Add banners to events calendar

[Amyh11325]

Changes

• Previously website's event calendar only showed the default banner on every event
• Now the website reads the banner link provided in the newsletter and displays the image at the link
  • If image link is invalid or unavailable, defaults to the default banner

Note: the banner link should link directly to a .png/.jpg image. If it links to google drive, the image must have the right permissions

Code

• Google drive share links must be transformed to directly export the image
• Only difficulty was that the CodeQL/Analyze scan is very strict and disallowed searching for "drive.google.com" within the link directly
  • Had to encode the URL and extract the host, then compare the host with "drive.google.com" to satisfy the code scanner

Testing

Used a test newsletter sheet (link), then copied various links into the newsletter banner column.

Case 1

Non Google Drive Link: https://i.ibb.co/99MH6Yz/277701596-1203931976807914-5430242111216078873-n.jpg

Case 2

Google Drive Link: https://drive.google.com/file/d/1HWHCg2dUIPKF-2g_l209SWbMKutlQsfB/view?usp=sharing

Case 3

Google Drive Link With Wrong Permissions: https://drive.google.com/file/d/1SmiQzf6MTBBNp6KNKD3zcvuNFUEPH71q/view?usp=sharing

Case 4

Invalid Link: i-am-an-invalid-link

Terminal warning:

Case 5

No Link

[ArshMalik02]

Looks good!