Split register "type" column

[angelina-momin]

Solves issues:

• #89 in splitting register "type" column to "type" and "venue"
• #85 in changing all URLs to lower case (was going to create a separate PR for that but then I found it easier to implement the changes already since I was redoing a lot of the code in codecheck repo)

Related codecheck PR #55

Changes made:

• Update register.csv by splitting the column "type" into "type" and "venue" where
  Venue = what is in brackets now
  Type = outside of brackets
• The venues subfolders were all changed to lowercase
• All featured.json, index.html, register.json and register.md files have been updated so that they now have a separate type and venue entry
• The tables for each venue no longer have "Type" and "Venue" column as they are redudant
• The number of codechecks was changed from string to int in all codecheckers, all venues and venues subcategories index.json files.
• Update libs versions.

[nuest]

Is the rendering code already capable to handle this change?

[nuest]

Ups, sorry, I see the draft tag now.

[angelina-momin]

@nuest the PR is ready to be reviewed. Made some changes and updated the description of this PR to reflect that.