add package creation with dependencies from CRAN, PyPI and Git repos

[altaf-ali]

add the following command:

 Usage: softpack-builder package create [OPTIONS] PACKAGES...                                                                                                                                                       
                                                                                                                                                                                                                    
 Create a package.                                                                                                                                                                                                  

 Arguments:
  *    packages      PACKAGES...  [default: None] [required]

 Options:
 --template        [python|r]  Package template. [default: None]
 --cran                        Get package from CRAN.           
 --pypi                        Get package from PyPI.                                                                                                                                                             
 --git             URL         Get package from Git. [default: None] 
 --branch          TEXT        Git branch. [default: None]           
 --commit          TEXT        Git commit hash. [default: None]      
 --tag             TEXT        Git tag. [default: None]              
 --help                        Show this message and exit.