Deprecate interactive mode in wskdeploy

[pritidesai]

We started Whisk Deploy with interactive mode a year back but now, we have come long way from prototyping mode to running in production. As of now, we have no use case for Interactive mode, so from code maintenance perspective, we have decided to deprecate and remove support for interactive mode from Whisk Deploy.

[csantanapr]

+1

[mrutkows]

@csantanapr already gutted 90% of this... the only part left is "report" which we plan to perhaps preserve as part of a "verify" step

[mrutkows]

@pritidesai we will preserve the interactive flag as a means to stop/verify assets before deployment

[pritidesai]

sure @mrutkows we can, in that case, can we rename --allow-interactive and -i to --dryrun (as per @lionelvillard's suggestion)?

Also, there are some code paths we need to delete specially in whiskclient:

grep -r "interactive" .
./deployers/whiskclient.go:// (5) prompt for values in interactive mode if any of them are missing
./deployers/whiskclient.go:     // If we still can not find the values we need, check if it is interactive mode.
./deployers/whiskclient_test.go:        assert.Nil(t, err, "Failed to read credentials in interactive mode")
./parsers/manifest_parser.go:                   // TODO() interactive ask for branch, AND consider YAML specification to allow key for branch
...