Catch OSError(errno.ENOSPC) and PermissionError

When the destination drive is not writable or has insufficient space,
these exceptions are raised during `run_installer`. Unless they are
caught and dealt with, `aqtinstall` requests that the user file a bug
report. This change catches these errors and prints a nice error message
instead of requesting a bug report.

aqt/exceptions.py

@@ -102,3 +102,11 @@ class UpdaterError(AqtException):
 
 class OutOfMemory(AqtException):
     pass
+
+
+class OutOfDiskSpace(AqtException):
+    pass
+
+
+class DiskAccessNotPermitted(AqtException):
+    pass