Add necessary files for creating a package

[yunchih]

Let's start with packaging for ArchLinux.

1. Need a configuration file template, a Systemd service file for running resrctl
2. Update the build steps in PKGBUILD.

P.S. I think we can move files related to packaging to a new subdirectory pkg.
Support for other distribution welcomed.

[Techievena]

@yunchih Can you please assign me to this and brief a bit more about what needs to be done?

[yunchih]

@Techievena yes, just do it.

1. Create a subdirectory pkg
2. Move PKGBUILD into it
3. Create Systemd service file and a template configuration file
4. Put the installation commands into PKGBUILD
5. The Systemd service file contains the startup command of resrc:

$ resrctl --config /etc/resrc/resrc.yaml

For step 3, 4, you can take ArchLinux's nginx as an example:
https://git.archlinux.org/svntogit/packages.git/tree/trunk?h=packages/nginx