DDF-487: Add created date and modified date filter support for catalog:dump

Also adds some tests for the original functionality.
Looks like it parses based on : http://joda-time.sourceforge.net/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateTimeParser%28%29
```
datetime          = time | date-opt-time
time              = 'T' time-element [offset]
date-opt-time     = date-element ['T' [time-element] [offset]]
date-element      = std-date-element | ord-date-element | week-date-element
std-date-element  = yyyy ['-' MM ['-' dd]]
ord-date-element  = yyyy ['-' DDD]
week-date-element = xxxx '-W' ww ['-' e]
time-element      = HH [minute-element] | [fraction]
minute-element    = ':' mm [second-element] | [fraction]
second-element    = ':' ss [fraction]
fraction          = ('.' | ',') digit+
offset            = 'Z' | (('+' | '-') HH [':' mm [':' ss [('.' | ',') SSS]]])
```
I think it would be good to add some examples to the wiki of the format it accepts. Not sure if we could also add them into this code. Maybe just a couple simple examples in the description? What do you think?