Add mailmergeagentconfig.json for the future

2 jobs for master in 25 minutes and 5 seconds (queued for 77 minutes and 31 seconds)
Status Job ID Name Coverage
  Build
passed #95424
build_clazy_clang_tidy

00:13:14

passed #95423
linux kf5-qt5 qt5.15

00:11:50

11.0%