Merge htmlformentry19ext module into htmlformentry

Now that htmlformentry requires a minimum version of OpenMRS 1.9.9, there is no longer any need for the htmlformentry19ext module to stay separate.

We should move the functionality from htmlformentry19ext into htmlformentry, and modify htmlformentry19ext to fail to start if the version of htmlformentry that is installed is a certain number or higher.

I believe the key steps would be to:

• Move EncounterProviderAndRoeleTag Handler into the "handler" directory in HFE API project with the other handlers

• Move EncounterRoleWidget, ProviderWidget, and ProviderAjaxAutoCompleteWidget into the "widget" directory in HFE API

• Move ProviderAndRoleElement and the ProviderStub into the "element" directory in HFE API

• Move "MatchMode", "ProviderTransformer" and "Transformer", "Predicate" into a new "util" directory in the HFE API project

• Do not copy over the ProviderByPersonNameComparator, but instead use the one now provided by core

• Move the utility methods in "HtmlFormEntryExtensions19Utils" into the existing "HtmlFormEntryUtil"--if there are any overlapping/duplicate methods, remove

• Incorporate the messages.propertes into the HFE messages.properties (be sure to properly push the translations into Transifex); remove the HFE 19ext Transifex project (if one exists)

• Add the EncounterRoleAndProviderTagHandler to the handler configuration in the HFE moduleApplicationContext (this replaces the setup in the HFE-Ext19 activator)

• Rename the "HtmlFormEntry19ExController" to "ProviderSearchController"; change the mapping of the getProviders method to the htmlformentry module instead of "htmlformentry19ext"; change all references to this controller (there may only be one--in the ProviderAjaxAutoCompleteWidget"

• Move all the tests over to the HFE module and confirm they work

• Modify htmlformentry19ext to fail to start if the version of htmlformentry that is installed is a certain number or higher.

• Fire up OpenMRS and confirm that the EncounterProviderAndRole tag still works, including all functionality as described here: https://wiki.openmrs.org/display/docs/HTML+Form+Entry+Module+HTML+Reference#HTMLFormEntryModuleHTMLReference