Added global exec path in site.pp

Added global exec path in site.pp, so path is not mandatory
to be specified in execs
Add Rustedhalo Jenkins public key
Added class rjil::db

This class does below stuffs
  Install mysql server packages
  Optionally format and mount mysql_data_disk to mysql_datadir
  create mysql database if not exists
  create databases and users and grants if not exists
Merge pull request #12 from bodepd/db

Added class rjil::db
Remove deprecated db_def define
Merge pull request #13 from bodepd/rm_db_def

Remove deprecated db_def define
Merge pull request #11 from hkumarmk/global_changes

Added global exec path in site.pp
Added rjil::memcached

Added memcached. memcached will be deployed on mc* nodes