feat: adding weighted random host selection strategy

[JuanLeee]

Description

Adding weighed random selection for host selection in order to prepare for future features.
User is able to add weights to different hosts to modify the likeliness of the particular host to be selected.

Manually tested for verification.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[karenc-bq]

Suggested change

	message = "HostSelector.NoHostsMatchingRole"
	logger.error(message, role)
	raise AwsWrapperError(Messages.get_formatted("HostSelector.NoHostsMatchingRole", role))
	message = Messages.get_formatted("HostSelector.NoHostsMatchingRole", role)
	logger.error(message, role)
	raise AwsWrapperError(message)

[JuanLeee]

logger.error already gets the message formatted:

def error(self, msg, *args, **kwargs):
    if not self.logger.isEnabledFor(logging.ERROR):
        return

    if args is not None and len(args) > 0:
        self.logger.error(Messages.get_formatted(msg, *args), **kwargs)
    else:
        try:
            self.logger.error(Messages.get(msg), **kwargs)
        except NotInResourceBundleError:
            self.logger.error(msg, **kwargs)

[karenc-bq]

Same comment as above