Refactor file view & render (#30227) (#30229)

Backport #30227 by wxiaoguang

The old code is inconsistent and fragile, and the UI isn't right.

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/shared/filetoolarge.tmpl

@@ -0,0 +1,4 @@
+<div class="tw-p-4">
+	{{ctx.Locale.Tr "repo.file_too_large"}}
+	{{if .RawFileLink}}<a href="{{.RawFileLink}}" rel="nofollow">{{ctx.Locale.Tr "repo.file_view_raw"}}</a>{{end}}
+</div>