Provide searchable archives for irc.qt.io

Ideally a web page at irc.qt.io that would provide:

• links to archive pages of the major channels
• text search functionality

To avoid privacy issues, only the non-private chats should be archived and indexed. Or we could have a list of the major channels we want to archive index. (#qtcommercial, #qtci, #digia-releases and so on)

This task was discussed and accepted during the Virtual QA Workshop in Oulu, September 27-29 2019, and it is listed in its tasklist.