Notifications framework enhancement ideas

[itisAliRH]

Suggestions that came up during the discussions in usegalaxy-au/elixir-biocommons-colab#5 related to the notifications framework:

• Display an appropriate icon in the notification card and prioritize certain notifications, using the source field in the notification schema. For example. when the source is admin, the notification will be displayed with the correct icon and won't be deleted until the user has seen it.
• Group notifications from the same source in a period with no other source notifications in between.
• Add a number indicator in the masthead icon.
• Show urgent and info/warning broadcasts at the same time when both groups are present.
• Use the carousel to view all news broadcasts.
• Dismiss unread broadcasts in one click
• Fix the CSS issue in the masthead tooltip.
• Replace the expiration time icon in notifications with inline text.
• Use one button in the notification card (tick to read and trash to delete).
• Stick urgent broadcasts to the top of the list.
• Show broadcasts on the notifications page.
• Have a sticky header when scrolling.
• Change the preferences button to filled and add an arrow icon.
• Keep expired broadcasts in the admin panel to reference and reuse their content for later.
• Use the left border colour for unread notifications instead of the blue dot
• Use a hovercard for the broadcast container and apply a border colour that corresponds with the variant.
• Remove icon blinking animation ([23.1] Remove blinking animation from icons #16471)