Move “Online Courses” documentation to a dedicated page

[julienrf]

The documentation about the Scala Center’s MOOCs was mixed with other online resources, in https://docs.scala-lang.org/learn.html:

We moved it to a new page at https://docs.scala-lang.org/online-courses.html:

Note that the new page uses the Scala 3 colors since the courses mainly use Scala 3.

The page /learn.html now contains a link to /online-courses.html:

(also note that the layout of the page is different and now shows the table of contents on the right)

We have also added entries to the navigation menus:

In the /online-courses.html page, we have moved the section “Learning Paths” up to the beginning, and we have included a general video about Scala Center MOOCs (the video is not available yet) :

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This PR requires one more action from visitors to see the Scala Center courses. Indeed, the path used to be index.html -> learn.html. It is now index.html -> learn.html -> online-courses.html. We could address this issue by putting a link to the online courses on the index.html page.

Update: I pushed a commit that includes back a link to /online-courses.html from the landing page:

However, I am not very happy with it because before the commit the whole gray rectangle was a link, whereas with the commit users now have to click exactly on the item title.

[SethTisue]

Great idea. I've often wanted to have a link to send people that just shows the Center's courses, and I never had one.

[SethTisue]

While I've got your attention, have you considered a new blog post about the courses? (Sharing whatever news there is to share, yes, but primarily simply reminding everyone, especially folks who are new to the community, that the courses exist and are being kept up-to-date.)

[bishabosha]

the structural changes seem fine, however as you mentioned every single item on the main docs page is no longer a button, you have to click exactly on the title in each box

[julienrf]

I agree @bishabosha, I have removed the last commit to revert that change only. Instead, I replaced the item “Online Resources” with “Online Courses”, and I included back a link to “Online Resources” from the page “Online Courses” (in the section at the bottom of the page).

I have also included the actual video.

Here is a screenshot of the landing page:

And the Online Courses page:

[bishabosha]

Looks good mostly, however now there is a divide: online courses appears in "First Steps" for Scala 2, but "More Detailed Information" for scala 3.

[julienrf]

True, the Scala 3 front page needs more work, but I would like to do it in a separate PR.