Improve --output flag for the commands to support all types of paths

[ishantiw]

Description

Create a generic utility for handling --output flag in Lisk commander. There are a few commands that use --output flag to output results to a specific directory along with filename or without it.

• By default we write to current directory cwd
• If a path is given in any form, with ~ or relative or absolute path needs to be resolved.
• If the path is given along with filename then choose that custom file name otherwise use a default one, preferably namespace passphrase:create to passphrase.json or keys:create to keys.json

Acceptance Criteria

• All commands using --output flag should have same behaviour
• Should have all unit tests

Additional Information