Consolidate Logos and update README header (#14136)

* Consolidate Logos and update README header

- Remove unused `logo-lg.png`, `logo-sm.png` and `logo-192.png`.
- Consolidate `favicon.svg` and `logo.svg` to just `logo.svg`.
- Remove Safari Mask icon, it seems to work fine with just `favicon.png` (no SVG support).
- Remove Fluid Icon. It only served Firefox and SVG works just fine there.
- Update customization instructions.
- Update README.md to use SVG icon, increase logo size and center it and badges.

* Update README_ZH.md

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

* Update README_ZH.md

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/setting/setting.go

@@ -1089,24 +1089,14 @@ func MakeManifestData(appName string, appURL string, absoluteAssetURL string) []
 		StartURL:  appURL,
 		Icons: []manifestIcon{
 			{
-				Src:   absoluteAssetURL + "/img/logo-lg.png",
-				Type:  "image/png",
-				Sizes: "880x880",
-			},
-			{
-				Src:   absoluteAssetURL + "/img/logo-512.png",
+				Src:   absoluteAssetURL + "/img/logo.png",
 				Type:  "image/png",
 				Sizes: "512x512",
 			},
 			{
-				Src:   absoluteAssetURL + "/img/logo-192.png",
-				Type:  "image/png",
-				Sizes: "192x192",
-			},
-			{
-				Src:   absoluteAssetURL + "/img/logo-sm.png",
-				Type:  "image/png",
-				Sizes: "120x120",
+				Src:   absoluteAssetURL + "/img/logo.svg",
+				Type:  "image/svg+xml",
+				Sizes: "512x512",
 			},
 		},
 	})