This allows relations to be set up between similar instances of
two templated units.

For example:

```puppet
systemd::manage_dropin{'user-aklog.conf':
  ensure     => present,
  unit       => 'user@.service',
  unit_entry => {
    'Documentation' => 'Run an aklog log before we start systemd --user',
    'After'         => ['user-aklog@%i.service'],
    'Requires'      => ['user-aklog@%i.service'],
  },
}
```

Previously the `%` character was considered illegal in a unit name.

Allow percent (%) character in unit names.

modulesync 7.2.0

Starting with

```puppet
class{ 'systemd':
  manage_reolved => true,
  cache          => false,
}
```

note that the cache parameter is currently `false` by default and an explicit
`Cache=no` would not be set. Instead nothing would be done.

This patch maintains backwards compatibility in that the default
still results in no modification to `/etc/systemd/resolved.conf`.

However an explicit setting of `cache => false` with this patch will now add
`Cache=no` to `resolved.conf`.

systemd::cache = false result was vague.

Deleting duplicate Key entries in types/unit/service.pp

…FERENCE.md using rake

CH: add ConditionPathIsMountPoint

It was previously impossible to set more than one environment variable:

e.g.

```puppet
systemd::manage_unit { 'test.service':
  unit_entry    => {
    'Description' => 'Bla',
  },
  service_entry => {
    'Type'        => 'oneshot',
    'Environment' => [
      'bla=foo',
      'bar=bla',
    ],
    'ExecStart'   => '/usr/bin/true',
  },
  enable        => false,
  active        => false,
}
```

* Fixes #404

Support multiple Environment Settings

modulesync 7.3.0

Allow `StartLimitIntervalSec` and `StartLimitBurst` to be set
in the `[unit]` section of a managed drop or unit file.

https://www.freedesktop.org/software/systemd/man/latest/systemd.unit.html#StartLimitIntervalSec=interval

Support `StartLimitIntervalSec` and  `StartLimitBurst`

Release 6.4.0