Refactor routers directory (#15800)

* refactor routers directory

* move func used for web and api to common

* make corsHandler a function to prohibit side efects

* rm unused func

Co-authored-by: 6543 <6543@obermui.de>

routers/web/swagger_json.go

@@ -0,0 +1,26 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package web
+
+import (
+	"net/http"
+
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/log"
+)
+
+// tplSwaggerV1Json swagger v1 json template
+const tplSwaggerV1Json base.TplName = "swagger/v1_json"
+
+// SwaggerV1Json render swagger v1 json
+func SwaggerV1Json(ctx *context.Context) {
+	t := ctx.Render.TemplateLookup(string(tplSwaggerV1Json))
+	ctx.Resp.Header().Set("Content-Type", "application/json")
+	if err := t.Execute(ctx.Resp, ctx.Data); err != nil {
+		log.Error("%v", err)
+		ctx.Error(http.StatusInternalServerError)
+	}
+}