Update the information of the translation page

[carlavilla]

Summary

Update the information of the translation page:

• Remove the Romain documentation project. The website is down.
• Update the Bulgarian URL and remove the mail list.
• Update the Traditional Chinese URL.
• Update the Estonian URL.
• Update the Korean URL.
• Remove obsolete URL in the Mongolian Documentation Project.
• Remove the Polish URL. The website is down.
• Remove the Spanish mailing list. Website down.

Test Plan

Compile the website

[bcr]

Looks good to me.