RFC: medusa-cli new plugin command

[agustif]

As I was having ideas from the new admin extensibility capabilities, and started building my plugin I feel like DX could be improved by adding a specific command to medusa-cli

Ex:
medusa plugin new plugin-name

• Creates ßimple package sans dependencies and with the instructions from https://docs.medusajs.com/development/plugins/create already done
• Asks for name, etc

Maybe a medusa plugin publish for a TUI streamlined too https://docs.medusajs.com/development/plugins/publish