JSON output

mentioned in issue #24

assigned to @HugoTrentesaux

Json output has to be thought about per command and we can have two scenario:

• showing data from rpc → why not
• showing data from indexer → useful but less flexible than curl with graphql request

At the moment I only implemented this on identity show. I will not do more than this in the short term.

unassigned @HugoTrentesaux

mentioned in merge request !20 (merged)