support shell autocomplete

[mr-c]

Using https://github.com/kislyuk/argcomplete

Here is how cwltool did it: https://github.com/common-workflow-language/cwltool/pull/1362/files

┆Issue is synchronized with this Jira Story ┆Issue Number: TOIL-1034

[unito-bot]

➤ Adam Novak commented:

There might be some odd interactions between argcomplete and ConfigArgparse, and the way we will build and run the parser on things other than the command line input sometimes.