Port to install.sh from Makefile
Make dir as droonga-engine user
Add droonga-engine service file
Add setting up service
Remove needless space
Move install scripts
Move default cli option to droonga-engine.yaml
Change shell
Fix variables
Fetch need files
Fix adding user command
Fix installation
Change cp to mv
Revert "Change shell"

This reverts commit 61a5f49fe1456eddb0ee8dfede170529e1dede19.
Replace `droonga-engine` to $NAME
Omit verbose path
Remove sudo prefix
Correct path of pid file
Log size of rest sessions, at the "trace" level.

It is for debugging of the issue #11
Move pid file configuration