Feature Request - add -offline option when run nextflow run

[lindaxiang]

As @junjun-zhang suggest, we could add -offline option when run nextflow run.

In our case, we don't really need nextflow to check github once a particular version of the workflow code is pulled done once.
Here are some information:
nextflow-io/nextflow@4a8cb93#diff-90f352e1beb0499b237c70a%5B%E2%80%A6%5D90ec4f63d2e59a402fa137ecdR183

This could potentially help to solve the issue: #153

[junjun-zhang]

This assumes the workflow code repo already has the desired version pulled down, how to do that is an open question.

[akachru-github]

The Open Access workflow is likely going to be rate limited by the Github api. This feature request should allow us to avoid this.

[rosibaj]

@akachru-github to schedule a chat for this with @jmimico regarding setting up a git server in RDPC

[lepsalex]

looks like it should be possible to setup our own "hub" using the Nextflow config instructions here: https://www.nextflow.io/docs/latest/sharing.html?highlight=private#private-server-configuration