update minimum required RAM to 64GB

Also adds more background explanation on time and RAM use,
as well as a hint that github issues are not good for
installation support.

CONTRIBUTING.md

@@ -15,9 +15,9 @@ Please make sure to add the following information:
  * the result you are getting
  * the expected result, preferably a link to the OSM object you want to find,
    otherwise an address that is as precise as possible
- 
- To get the link to the OSM object, you can try the following:
- 
+
+To get the link to the OSM object, you can try the following:
+
  * go to https://openstreetmap.org
  * zoom to the area of the map where you expect the result and
    zoom in as much as possible
@@ -26,7 +26,7 @@ Please make sure to add the following information:
  * find the object of interest in the list that appears on the left side
  * click on the object and report the URL back that the browser shows
 
-### When Reporting Problems with your Installation...
+### When Reporting Bugs...
 
 Please add the following information to your issue:
 
@@ -38,6 +38,9 @@ Please add the following information to your issue:
    if you run from the git repo, the output of `git rev-parse HEAD`)
  * (if applicable) exact command line of the command that was causing the issue
 
+Bug reports that do not include extensive information about your system,
+about the problem and about what you have been trying to debug the problem
+will be closed.
 
 ## Workflow for Pull Requests