Include query in sign in redirect (#11579)

* Include query in sign in redirect

Include query string in ctx.Data["SignInLink"] so people are redirected to the right page after singing in. Fixes case of:

Visit:

 https://try.gitea.io/mrsdizzie/testcase/issues?q=&type=all&sort=&state=open&labels=7071&milestone=0&assignee=0

Sign in, then redirected to:

 https://try.gitea.io/mrsdizzie/testcase/issues

Create a new "SignInLink" instead of updating the existing "Link" because too many places in the code assume "Link" won't have a query

* Apply suggestions from code review

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/context/context.go

@@ -242,6 +242,7 @@ func Contexter() macaron.Handler {
 		}
 		ctx.Data["Language"] = ctx.Locale.Language()
 		c.Data["Link"] = ctx.Link
+		ctx.Data["CurrentURL"] = setting.AppSubURL + c.Req.URL.RequestURI()
 		ctx.Data["PageStartTime"] = time.Now()
 		// Quick responses appropriate go-get meta with status 200
 		// regardless of if user have access to the repository,