Replace Echo logger with slog. (#67)

* Replace Echo logger with slog.

pkg/log/log_test.go

@@ -0,0 +1,21 @@
+package log
+
+import (
+	"testing"
+
+	"github.com/labstack/echo/v4"
+	"github.com/mikestefanello/pagoda/pkg/tests"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCtxSet(t *testing.T) {
+	ctx, _ := tests.NewContext(echo.New(), "/")
+	logger := Ctx(ctx)
+	assert.NotNil(t, logger)
+
+	logger = logger.With("a", "b")
+	Set(ctx, logger)
+
+	got := Ctx(ctx)
+	assert.Equal(t, got, logger)
+}