feat(gbuild): new programs from template

[clearloop]

Resolves #4094

$ cargo-gbuild new -h
Create a new gear program

Usage: cargo-gbuild new <PATH>

Arguments:
  <PATH>  Path of the gear program to be created

Options:
  -h, --help  Print help
  
$ cargo-gbuild new sails-program
cargo-gbuild new sails-program
  Downloading https://github.com/MedovTimur/template.git
     Finished sails-program

NOTE: cargo-gbuild init is not implemented, imo it is not frequently used, can add it as well in this PR if anybody think it is necessary

@gear-tech/dev

[breathx]

Have you tested it manually? If yes, feel free to merge