move implementations to external repos (#17)

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

config/default.go

@@ -6,9 +6,7 @@ import (
 	"time"
 
 	"github.com/unistack-org/micro/v3/config/loader"
-	"github.com/unistack-org/micro/v3/config/loader/memory"
 	"github.com/unistack-org/micro/v3/config/reader"
-	"github.com/unistack-org/micro/v3/config/reader/json"
 	"github.com/unistack-org/micro/v3/config/source"
 )
 
@@ -42,19 +40,12 @@ func newConfig(opts ...Option) (Config, error) {
 }
 
 func (c *config) Init(opts ...Option) error {
-	c.opts = Options{
-		Reader: json.NewReader(),
-	}
+	c.opts = Options{}
 	c.exit = make(chan bool)
 	for _, o := range opts {
 		o(&c.opts)
 	}
 
-	// default loader uses the configured reader
-	if c.opts.Loader == nil {
-		c.opts.Loader = memory.NewLoader(memory.WithReader(c.opts.Reader))
-	}
-
 	err := c.opts.Loader.Load(c.opts.Source...)
 	if err != nil {
 		return err