Rename 'tx' command to 'transfer'

Rename tx command to transfer. To avoid confusion with a transaction in general (certification, membership)

changed milestone to %0.11.0

added CLI D: Transfer enhancement labels

added To Do label

assigned to @moul

mentioned in commit fb8c1d26

mentioned in commit 2e9b77b1

mentioned in merge request !218 (merged)

mentioned in commit 4498d1d1

closed with merge request !218 (merged)