New systemd::manage_unit and systemd::manage_dropin type

Example
```puppet
systemd::manage_unit{ 'myrunner.service':
  $unit           => {
    'Description' => 'My great service',
  },
  $service        => {
    'Type'        => 'oneshot',
    'ExecStart'   => '/usr/bin/doit.sh',
  },
  $install        => {
    WantedBy      => 'multi-user.target',
  },
}
```

will generate and manage a new systemd unit from a template.

The type `systemd::manage_dropin` is similar
for drop in files.

Author: traylenator

README.md

@@ -59,6 +59,30 @@ systemd::unit_file { 'foo.service':
 }
 ```
 
+### unit files from parameters
+
+Create a unit file from parameters
+
+```puppet
+systemd::manage_unit { 'myrunner.service':
+  $unit_entry    => {
+    'Description' => 'My great service',
+  },
+  $service_entry => {
+    'Type'       => 'oneshot',
+    'ExecStart' => '/usr/bin/doit.sh',
+  },
+  $install_entry => {
+    'WantedBy' => 'multi-user.target',
+  },
+  enable         => true,
+  active         => true,
+}
+```
+
+The parameters `unit_entry`, `service_entry` and `install_entry` populate the
+`[Unit]`, `[Service]` and `[Install]` sections of the generated unit file.
+
 ### drop-in files
 
 Drop-in files are used to add or alter settings of a unit without modifying the
@@ -105,6 +129,21 @@ systemd::dropin_files:
     source: puppet:///modules/${module_name}/foo.conf
 ```
 
+### drop-in files from parameters
+
+```puppet
+systemd::manage_dropin { 'myconf.conf':
+  ensure        => present,
+  unit          => 'myservice.service',
+  service_entry => {
+    'Type'      => 'oneshot',
+    'ExecStart' => ['', '/usr/bin/doit.sh'],
+  },
+}
+```
+
+The filename of the drop in. The full path is determined using the path, unit and this filename.
+
 ### modules-load.d
 
 Create a file entry for modules-loads directory and start