feat(commands): more commands (#30)

- I wrote a scripts to copy and generate all commands missing in iris
from fig repo: https://github.com/withfig/autocomplete
- Add a new script to generate commands docs about which commands
currently are inside commands folder
377d4aac663590e504fe39a92eb4dac4cbd333b2
- Add more icons e64d4e70a1db61e62053460a882e093bd6373ab1

commands/sys/exec.go

@@ -0,0 +1,12 @@
+package sys
+
+import (
+	"github.com/versenilvis/iris/commands/core"
+)
+
+func init() {
+	core.Register(&core.Spec{
+		Name:        "exec",
+		Description: "Replace the current shell with a program",
+	})
+}