New topic linking to error codes

Include a new menu item "Error Codes" under Troubleshooting section of all CBL platforms. It should take users to the corresponding API link that lists the errors — see slack for details
CBL-=

• C. https://docs.couchbase.com/mobile/3.0.0-beta02/couchbase-lite-c/C/html/group__errors.html#gad43e348ca76e9a8fe7c10ec916bf0528. 
• .NET https://docs.couchbase.com/mobile/3.0.0-beta02/couchbase-lite-net/api/Couchbase.Lite.CouchbaseLiteError.html.
• ObjC. https://docs.couchbase.com/mobile/3.0.0-beta02/couchbase-lite-objc/Constants.html
• Swift. Nothing in API docs. (looks like the ObjC constants get bridged up). So the only option to link to https://docs.couchbase.com/mobile/3.0.0-beta02/couchbase-lite-swift/.  Hopefully not confusing to devs to be pointed to ObjC spec! Also the   CBLErrors.h header is included in the downloaded package. Thats anther option that what developers can refer to
• Android. https://docs.couchbase.com/mobile/3.0.0-beta02/couchbase-lite-android/com/couchbase/lite/CBLError.Code.html.

  * Java. https://docs.couchbase.com/mobile/3.0.0-beta02/couchbase-lite-java/com/couchbase/lite/CBLError.Code.html

There is a related ticket for the dev team to update the description in the API specs but you dont have to wait on that https://issues.couchbase.com/browse/CBL-2550 (edited)