service: Convert MigrationManager to C++, take 2
service: Convert MigrationManager to C++, take 2

Signed-off-by: Pekka Enberg <add4fcd06328a394f0ad91feda7ee057316dc5ed@cloudius-systems.com>

victorbriz/scylla,victorbriz/scylla,rluta/scylla,dwdm/scylla,capturePointer/scylla,dwdm/scylla,avikivity/scylla,dwdm/scylla,gwicke/scylla,raphaelsc/scylla,acbellini/scylla,glommer/scylla,linearregression/scylla,kangkot/scylla,rentongzhang/scylla,linearregression/scylla,shaunstanislaus/scylla,capturePointer/scylla,kjniemi/scylla,victorbriz/scylla,rentongzhang/scylla,bowlofstew/scylla,aruanruan/scylla,justintung/scylla,aruanruan/scylla,duarten/scylla,bowlofstew/scylla,scylladb/scylla,rluta/scylla,justintung/scylla,bowlofstew/scylla,asias/scylla,capturePointer/scylla,eklitzke/scylla,shaunstanislaus/scylla,guiquanz/scylla,glommer/scylla,respu/scylla,glommer/scylla,raphaelsc/scylla,phonkee/scylla,wildinto/scylla,kangkot/scylla,phonkee/scylla,tempbottle/scylla,wildinto/scylla,kjniemi/scylla,tempbottle/scylla,senseb/scylla,stamhe/scylla,justintung/scylla,scylladb/scylla,kjniemi/scylla,gwicke/scylla,respu/scylla,duarten/scylla,linearregression/scylla,avikivity/scylla,senseb/scylla,stamhe/scylla,avikivity/scylla,phonkee/scylla,stamhe/scylla,senseb/scylla,aruanruan/scylla,guiquanz/scylla,respu/scylla,rentongzhang/scylla,raphaelsc/scylla,scylladb/scylla,acbellini/scylla,eklitzke/scylla,tempbottle/scylla,shaunstanislaus/scylla,rluta/scylla,asias/scylla,wildinto/scylla,kangkot/scylla,scylladb/scylla,duarten/scylla,acbellini/scylla,asias/scylla,gwicke/scylla,guiquanz/scylla,eklitzke/scylla