WIP allow sorting by integers

This is a POC. If it is seen to be a viable solution I will clean it up :)

DoctrineDBAL does not currently allow sorting on integer properties. This means that when you perform an ORDER BY on a set of numbers the result may be: `10, 100, 1000, 2, 20` etc.

The best solution *would* be to use the `CAST` keyword (e.g. `ORDER BY CAST([sulu:order])`) but CAST will only ever work on static operands (e.g. `CAST('12' AS LONG)`)

This PR separates the property values into three separate columns, `props`, `long_props` and `decimal_props` and orders by all three.

````
SELECT ... WHERE ...  ORDER BY 
CAST(EXTRACTVALUE(n0.long_props, '//sv:property[@sv:name="sulu:order"]/sv:value[1]') AS INTEGER), 
CAST(EXTRACTVALUE(n0.decimal_props, '//sv:property[@sv:name="sulu:order"]/sv:value[1]') AS DECIMAL),
EXTRACTVALUE(n0.props, '//sv:property[@sv:name="sulu:order"]/sv:value[1]')
````

This seems to work.
I think it is BC (with a schema update) -- the properies are merged from the three columns, so existing properties should continue to work, whilst updates and new nodes will populate the new columns. Although it would be optimal to walk the tree to upgrade the nodes eagerly and take advantage of the feature.