In order to widely use filesystem interface in airshipctl
there is need to move it to separate package to avoid
importing unnecessary dependencies from document
package and, as a consequence, possible cyclic dependencies.
* filesystem moved from document/fs to pkg/fs
Change-Id: I3b6298462f03db43594a9fa26bf23ab7687c5589
Signed-off-by: Ruslan Aliev <raliev@mirantis.com>
Relates-To: #415