Support --render options for skaffold deploy.

[tejal29]

In #1737 @andsens mentioned, pointed out a use case where users would want to inspect skaffold deploy generated manifests.

I am thinking this would also be required for

Expected behavior

when you run skaffold with --dryrun flag, all the manifests it generates should be dumped in ./out directory.

Actual behavior

Right now, users need to run skaffold with -v=debug flag to grab the generated manifests from output.

Information

• Skaffold version: v0.5.0-1901-g1d077079-dirty
• Operating system: ...
• Contents of skaffold.yaml:

<paste your skaffold.yaml here>

Steps to reproduce the behavior

[nkubala]

now that we've separated out the tagging interface and gotten rid of the "unstable" taggers, this should be possible. dry run mode for skaffold build would give the user the images skaffold would have built, though for skaffold deploy we'll need to rethink it (or possibly just address #922 first).

dry run mode for skaffold run would probably provide the user with both the images that would have been built as well as the templated manifests, and skaffold dev would do the same thing (no dev loop).

[alnr]

Note you can pass the --dry-run flag to your deployer of choice, but output is interleaved with skaffold logging (see #1937 (comment))

[tejal29]

I think we should add a flag to deploy to dump the manifests generated as mentioned

[tejal29]

Related to #1187
Closing this as its dupe