Improve init command description log messages

[ManuGowda]

Expected behavior

• Update init description to Commands relating to bootstrapping a blockchain application or plugin using lisk-sdk
• Update message to "forging_info.json" and "accounts.json" files saved at "./.secrets/mainnet"
• Update message to Create custom plugin as a standalone package .

Actual behavior

• init command description Bootstrap a lisk-sdk project.
• Update message The files, "forging_info.json" and "accounts.json" have been moved to "./.secrets/mainnet"
• Update init:plugin desc Creates custom plugin as a standalone package with dependencies.

Steps to reproduce

bin/run init

Which version(s) does this affect? (Environment, OS, etc...)

development