Update CONTRIBUTING.md (gorhill#3889)

* Update CONTRIBUTING.md

Completely revamped and expanded document.

* Update CONTRIBUTING.md

Remove reference to uBO Legacy.

CONTRIBUTING.md

@@ -1,5 +1,31 @@
-# Submitting issues
+# Contributions
 
-Submit on <https://github.com/uBlockOrigin/uBlock-issues/issues>.
+Refer to the following sections to direct you to the appropriate destination. Thank you in advance for your help.
 
-Issue tracker here is read-only for non-[prior contributors](https://github.com/gorhill/uBlock/graphs/contributors).
+---
+
+### Translations
+
+Help translate uBO via [Crowdin](https://crowdin.com/project/ublock).
+
+---
+
+### Reporting Issues
+
+The issue tracker in this repository is deprecated. Use the links below to guide you to where you need to report your issue.
+
+#### Support Forum
+
+For support, questions, or help, visit [/r/uBlockOrigin](https://www.reddit.com/r/uBlockOrigin/).
+
+#### Filter List Issues
+
+Report issues with filter lists or broken website functionality in the [uAssets issue tracker](https://github.com/uBlockOrigin/uAssets/issues).
+
+#### uBlock Origin (uBO) Issues
+
+Report issues with uBO in the [uBO issue tracker](https://github.com/uBlockOrigin/uBlock-issues/issues).
+
+#### uBO Lite (uBOL) Issues
+
+Report issues specific to the Manifest Version 3 (MV3) variant in the [uBOL issue tracker](https://github.com/uBlockOrigin/uBOL-issues/issues).