Replace www-path with www-proxy option for development (#248)

By adding a new ENV variable called `WOODPECKER_WWW_PROXY` it is possible to serve a webinterface via a proxy configured by the `WOODPECKER_WWW_PROXY` value for development instead of serving the interface from the bundled code or from some folder location as the old `WOODPECKER_WWW` option allowed. Using a proxy allows developing the UI with hot-reloading.

server/web/web.go

@@ -19,9 +19,7 @@ import (
 	"crypto/md5"
 	"fmt"
 	"html/template"
-	"io/ioutil"
 	"net/http"
-	"path/filepath"
 	"time"
 
 	"github.com/woodpecker-ci/woodpecker/model"
@@ -45,10 +43,6 @@ func New(opt ...Option) Endpoint {
 		f(opts)
 	}
 
-	if opts.path != "" {
-		return fromPath(opts)
-	}
-
 	return &website{
 		fs:   dist.New(),
 		opts: opts,
@@ -58,19 +52,6 @@ func New(opt ...Option) Endpoint {
 	}
 }
 
-func fromPath(opts *Options) *website {
-	f := filepath.Join(opts.path, "index.html")
-	b, err := ioutil.ReadFile(f)
-	if err != nil {
-		panic(err)
-	}
-	return &website{
-		fs:   http.Dir(opts.path),
-		tmpl: mustCreateTemplate(string(b)),
-		opts: opts,
-	}
-}
-
 type website struct {
 	opts *Options
 	fs   http.FileSystem