Jira jenkins

Please review code for supporting change test execution status in JIRA
I just realized now whether we don't want `jira_password` and `jira_username` to be passed together in one argument, like it is being done for Browserstack credentials. Because passing one without the other does not make much sense.

Also, if we had only one argument, we could use it as a flag whether user want to use JIRA integration or not (we would not need to introduce a new one)