Decouple the different contexts from each other (#24786)

Replace #16455

Close #21803

Mixing different Gitea contexts together causes some problems:

1. Unable to respond proper content when error occurs, eg: Web should
respond HTML while API should respond JSON
2. Unclear dependency, eg: it's unclear when Context is used in
APIContext, which fields should be initialized, which methods are
necessary.


To make things clear, this PR introduces a Base context, it only
provides basic Req/Resp/Data features.

This PR mainly moves code. There are still many legacy problems and
TODOs in code, leave unrelated changes to future PRs.

modules/context/context_request.go

@@ -6,36 +6,9 @@ package context
 import (
 	"io"
 	"net/http"
-	"net/url"
-	"strconv"
 	"strings"
-
-	"github.com/go-chi/chi/v5"
 )
 
-// RemoteAddr returns the client machine ip address
-func (ctx *Context) RemoteAddr() string {
-	return ctx.Req.RemoteAddr
-}
-
-// Params returns the param on route
-func (ctx *Context) Params(p string) string {
-	s, _ := url.PathUnescape(chi.URLParam(ctx.Req, strings.TrimPrefix(p, ":")))
-	return s
-}
-
-// ParamsInt64 returns the param on route as int64
-func (ctx *Context) ParamsInt64(p string) int64 {
-	v, _ := strconv.ParseInt(ctx.Params(p), 10, 64)
-	return v
-}
-
-// SetParams set params into routes
-func (ctx *Context) SetParams(k, v string) {
-	chiCtx := chi.RouteContext(ctx)
-	chiCtx.URLParams.Add(strings.TrimPrefix(k, ":"), url.PathEscape(v))
-}
-
 // UploadStream returns the request body or the first form file
 // Only form files need to get closed.
 func (ctx *Context) UploadStream() (rd io.ReadCloser, needToClose bool, err error) {