Add a tab to display lesson details in Agenda.

[AhmedNSidd]

@DSchriemer @Nppatel97 I need your guys' help on something frontend. This is how our agenda page looks like right now.

There are some issues lying around like #135, #121, and #126 that require the use of a place to list details about the lesson. When I say details I mean like a one liner detail. One liner details like: "This lesson has conflicting timings with another one of your lessons." I was thinking we could have a rectangle on top of the lesson box where we could list that detail. What I need you guys to do right now is give me some suggestions on the best way we could display that information. My suggestion is a rectangle extending from the top of the lesson box. If you guys have any other innovative ways of doing it, I WANNA HEAR IT!

[Nppatel97]

My suggestion is to have a tiny yellow warning sign beside the title which on hover or click displays the warning message. This implementation would be a little easier to do for both mobile and desktop versions. What do you think @AhmedNSidd and @DSchriemer?

Edit: We can put the message box as absolute so it doesn't fiddle with the dimensions of the actual lessons box

[AhmedNSidd]

That's a good idea. I like it. I think we should place the warning sign in the beginning of the title. Something like this would work nicely: https://fontawesome.com/icons/exclamation-triangle?style=solid

Then if you hover over anywhere on the title, it'll give you the details.