Move context from modules to services (#29440)

Since `modules/context` has to depend on `models` and many other
packages, it should be moved from `modules/context` to
`services/context` according to design principles. There is no logic
code change on this PR, only move packages.

- Move `code.gitea.io/gitea/modules/context` to
`code.gitea.io/gitea/services/context`
- Move `code.gitea.io/gitea/modules/contexttest` to
`code.gitea.io/gitea/services/contexttest` because of depending on
context
- Move `code.gitea.io/gitea/modules/upload` to
`code.gitea.io/gitea/services/context/upload` because of depending on
context

services/context/utils.go

@@ -0,0 +1,38 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package context
+
+import (
+	"strings"
+	"time"
+)
+
+// GetQueryBeforeSince return parsed time (unix format) from URL query's before and since
+func GetQueryBeforeSince(ctx *Base) (before, since int64, err error) {
+	before, err = parseFormTime(ctx, "before")
+	if err != nil {
+		return 0, 0, err
+	}
+
+	since, err = parseFormTime(ctx, "since")
+	if err != nil {
+		return 0, 0, err
+	}
+	return before, since, nil
+}
+
+// parseTime parse time and return unix timestamp
+func parseFormTime(ctx *Base, name string) (int64, error) {
+	value := strings.TrimSpace(ctx.FormString(name))
+	if len(value) != 0 {
+		t, err := time.Parse(time.RFC3339, value)
+		if err != nil {
+			return 0, err
+		}
+		if !t.IsZero() {
+			return t.Unix(), nil
+		}
+	}
+	return 0, nil
+}