Fix reset error issue #757: caused errors when there were active wor…

[pagrubel]

…kflows. This commit performs the following to solve the errors:

• allow reset when there are active workflows, remove workflows
• add ability to remove or cancel paused workflows
• check workflows for active states
• warn user there are active states before continuing
• stop all processes for active workflows
• add get_workflow_list method to eliminiate duplicate code
• make response text message clearer to read in code
• add timestamp to name for unique backup if archive flag is set
• simplify complexity of reset function
• print warning and possible course of action when intializing workflows cause directory removal to fail

Resolves: #757

[pagrubel]

This PR should be ready to merge. There is some discussion in #793 (closed) if you want to follow why this was implemented by removing all workflows. I could not remove initializing workflows, but the bee_workdir can be removed manually by the user once the reset is complete. Since this is mostly for developers I just added a message to tell them to do that.