adding selinux file resource for check_yum and other custom plugins

I have tested on OracleLinux.  Based selinux properties from existing checks provided by plugin package -

# ls -axlZ check_load
-rwxr-xr-x. root root system_u:object_r:nagios_system_plugin_exec_t:s0 check_load
# ls -axlZ check_yum
-rwxr-xr-x. root root system_u:object_r:bin_t:s0       check_yum

After puppet agent run -
# ls -axlZ check_yum
-rwxr-xr-x. root root   system_u:object_r:nagios_system_plugin_exec_t:s0 check_yum