Prepare switch to mozilla88

• #40392 (closed) (Rebase tor-browser patches to 88.0b4)
• tor-browser-build#40266 (closed) (Make the list of components updates for switch to mozilla88-based Fenix)
• tor-browser-build#40259 (closed) (Update components for switch to mozilla88-based Fenix)
• #40396 (closed) (Review developer notes for Firefox 88)
• #40397 (closed) (Review GeckoView Changelog for gv88)
• #40398 (closed) (Review closed mozilla88 bug)
• #40399 (closed) (Rebase 10.5 patches on 88.0)
• android-components#40048 (closed) (Rebase android-components patches for Fenix 88 beta X builds)
• android-components#40050 (closed) (Rebase android-components patches for Fenix 88)
• android-components#40049 (closed) (Review MozAC Changelog for Fenix88)
• fenix#40154 (closed) (Rebase Fenix patches to Fenix 88 beta 4)
• fenix#40157 (closed) (Rebase Fenix patches to Fenix 88.1.0)
• tor-browser-spec#40017 (closed) (FF88 network audit)
• tor-browser-bundle-testsuite#40022 (closed) (Update tests when switching to Fenix 88)
• fenix#40155 (closed) (Review changes for Fenix88)
• #40406 (closed)