fix(service): solve pid files permissions by detecting who run script

If service is run as 'root' then we run mast process as '$localUser' user
so the 'www-data' user can start/stop it. Otherwise we run as 'www-data' user.

fixes #43
refactor(service): make MAX_LATENCY global
refactor(service): create 'kill_and_clean()' function
fix(service): remove zombie process when latency fails

fixes #45
docs(service): update function docs blocks
refactor(service): extract 'restart' as function
fix(service,hotfix): rename duplicate 'start' as 'restart'
style(service,kill_and_clean): lower case local variable 'NAME' to 'name'