[RJA-xxx][fix] cancel & reset buttons status
Merge pull request #807 from bugzmanov/fb-remoting

[RJA-xxx][fix] cancel & reset buttons status
[RJA-1661] [fix] - JS: Polling stops if REST request fails

Poller option to reschedule on error added.
Merge pull request #808 from rsvato/agents

[RJA-1661] [fix] - JS: Polling stops if REST request fails
Merge pull request #809 from ddurnev/agents

[RJA-1787][fix]: variables - always show empty drop-down in case of empty values map.
[RJA-1789][fix]: allow user to create instances only if at least one environment is accessible