enable to use hash args in execute! command

a lot of commands are required xml file for configuration,
so users are forced to place xml file and delete it after command.

```ruby
filename = ...

template filename do
  
end

jenkins_job 'foo' do
  config filename
end

file filename do
  action :delete
end
```

I think it it better to use xml string for configuration

like this

```ruby
jenkins_job 'foo' do
  xml xml_string
end
```

and execute! will be called like this

```ruby
executor.execute!('create-job', input: xml_string)
``` 

so, at first, I enable to use hash args in execute! method.