Added registry configuration hash option

Typo fix: 'oder' -> 'or'

…into agray1017-configs

And fix merge conflicts and syntax

the root cause needs to be found first and then fixed. currently
it fails with:

```
Failure/Error: it { is_expected.to
contain_class('gitlab::install').that_comes_before('gitlab::config') }
ArgumentError:
  No title provided and "gitlab::config" is not a valid resource
  reference
```

See also
https://docs.puppet.com/puppet/3.8/reference/system_requirements.html#ruby

```
> cat /etc/gitlab-runner/config.toml
concurrent = 1
```

which limits the total number of concurrent jobs among all runners to
one.

This adds a parameter, `concurrent`, to the `gitlab::cirunner` class to
manage this setting.  By default, the setting is left unmanaged, but
the parameter can be set to any integer >= 1 to enable management of it.

Closes #71

Contributed by @iamjamestl. Thanks a lot!