Persistent directory for container in execdriver

This is needed for persistent namespaces

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Test on execdriver dir behavior

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>
Merge pull request #7973 from LK4D4/persist_execdriver_dir

Persist execdriver dir