ability to override or append to registry

Problem:
Currently registry is hardcoded, the struct is very simple right now

Lines 3 to 7 in 587d6f5

    
           type Registry []Stack 
        
           type Stack struct { 
        
           	Name          string 
        
           	ModuleSources []string 
        
           }

that means to build a module u must also build your own zero binary.

Potential solution:
Maybe we can allow something like ~/.zero-registry.yaml, we can just add some annotations to the struct and parse the config, allowing users to customize registry for their own use

Working on it

Hey everyone! I created the PR #470 trying to solve it. Please let me know if I should change anything. Thanks!

PR merged and v0.2.5 released: https://github.com/commitdev/zero/releases/tag/v0.2.5
Thanks again!

	type Registry []Stack
	type Stack struct {
	Name string
	ModuleSources []string
	}