New commands & refectoring
* fnctl: refactor code to improve reuse between commands
build, bump and publish (formerly update) share a lot of code,
this refactor ensure their logic are correctly reused. It renames
update to publish, so it would be a strong diff between "update"
and build.
* fnctl: remove unnecessary dependency for build and bump
* fnctl: improve code reuse between bump, build and publish
Unify the use of walker function in all these three commands and
drop dry-run support.
* Code grooming
- errcheck
* fnctl: update README.md to be in sync with actual execution output
* fnctl: move scan function to commoncmd structure
* fnctl: change verbose flag handling does not use global variable anymore
