Migrate Etherpad to CodiMD

• create new server
• install CodiMD with notes-test.typo3.org hostname
• connect CodiMD to LDAP
• export pads (test run)
• fix pad names (test run)
• Twitter announcement for testing
• collect feedback and decide about further proceedings at the 2020/04/07 team meeting
• announce downtime
• Update CodiMD 2.0.1
• announce downtime start
• disable Etherpad access
• disable old monitoring
• export pads (final run)
• fix pad names (final run)
• switch CodiMD to notes.typo3.org
• check new monitoring
• Twitter announcment, mention CodiMD_Dev
• remote notes-test.typo3.org DNS record
• cleanup chef proxy data bags
• knife client delete
• knife node delete
• update server index
• remove server from monitoring
• remove server