refactor(commands): separate commands and its core into two folders (#32)

- I think it would be better if one for commands only, one for the spec
handling core logic so people won't be confused by the core logic inside
the commands folder (cleaner I guess)
- Regen docs

commands/ops/coda.go

@@ -1,14 +1,14 @@
 package ops
 
 import (
-	"github.com/versenilvis/iris/commands/core"
+	"github.com/versenilvis/iris/spec"
 )
 
 func init() {
-	core.Register(&core.Spec{
+	spec.Register(&spec.Spec{
 		Name:        "coda",
 		Description: "Coda CLI - interact with Coda docs and tables",
-		Subcommands: []core.Subcommand{
+		Subcommands: []spec.Subcommand{
 			{Name: "init", Description: "Initialize an empty project with the recommended settings and dependencies"},
 			{Name: "execute", Description: "Execute the formula and print the output to the terminal"},
 			{Name: "formula", Description: "Formula name to execute"},
@@ -25,7 +25,7 @@ func init() {
 			{Name: "option", Description: "Currently the only supported option is 'timerStrategy'"},
 			{Name: "value", Description: "Value to set for the option"},
 		},
-		Options: []core.Option{
+		Options: []spec.Option{
 			{Name: "--dynamicUrl", Description: "The URL to sync from"},
 			{Name: "--name", Description: "The desired Pack name"},
 			{Name: "--description", Description: "The Pack description"},