ARI: Added new functionality to unload a single module.

An http request can be sent to unload an Asterisk module. If the
module can not be unloaded or is already unloaded, an error response
will be returned.

The command "curl -v -u user:pass -X DELETE 'http://localhost:8088
/ari/asterisk/modules/{moduleName}'" (or something similar, depending
on configuration) can be run in the terminal to access this new
functionality.

For more information, see:
https://wiki.asterisk.org/wiki.display/~bford/Asterisk+ARI+Resource

* Added new ARI functionality
* Asterisk modules can be unloaded through http requests

ASTERISK-25173

Change-Id: I535a95f5676deb02651522761ecbdc0b00b5ac57