Refactor resource model definition

Can we just begin by cutting down the existing project.dtd to just node and setting tags?

Is it possible to drop the DTD all together, or at least not make it a requirement of existing in the document when it's read by RunDeck? It can be optional. If it's present then use it?

we can do both

I'm all for dumping the DTD decl for the resources.xml doc. Not sure if that will have an annoying consequence elsewhere in the code base.

we can use dtd declaration for our own generated xml, but not require it on
input

Yaml version?

My yaml thought is just to allow arbitrary entries in the data map:

mynode:
  name: mynode
  hostname: blah
  arbitrary: value

other options for the xml format. i will implement all of these to provide some variety in input syntax:

 <node name="mynode">
    <attribute name="attr1">value</attribute>
 </node>

and

 <node name="mynode" attr1="value">
 </node>

(from [5c5508dc5a0d6bae94c5b2b0dd780ac854028592]) Refactor node/resources to add attributes [#114 Refactor resource model definition] https://github.com/dtolabs/rundeck/commit/5c5508dc5a0d6bae94c5b2b0d...

(from [163e4d06710f6bd15dc236cb1f250786dec1f6dd]) Update documentation for resources v1.3 [#114 Refactor resource model definition] https://github.com/dtolabs/rundeck/commit/163e4d06710f6bd15dc236cb1...