On TMX import:

• filter TMX for duplicates on import always
• in case someone imports a TMX into an existing TM:
  • make sure, write requests are blocked for the TM
  • export the TM to tmx before import
  • merge it with the to be imported TMX
  • capilize author names in merged TMX
  • filter duplicates
    • as configured by params from https://jira.translate5.net/browse/TRANSLATE-5034 in sysconfig.
  • Import TMX into a new empty one
  • replace that languageresource table points to the new one instead of the old
  • delete the old TM