Implement frictionless convert command for metadata in CLI

[roll]

Overview

We now have some metadata conversion capabilities built into the framework like to_markdown, to_er_diagram, etc We'd like to expose this functionality to the cli:

frictionless convert package.json <path> --yaml
frictionless convert package.json <path> --er-diagram
frictionless convert package.json <path> --markdown
# more

Note that this action only handle metadata for the data conversion we use frictinless transform (at least for now -- later we might think about extending this command to data conversion as a shorcut for the transform)

[roll]

DONE in #1195