Re: RM5576: Improve error messaging if the storage and logdirectories cannot be created

Patch for $SUBJECT attached. Sample output:

python web/pgAdmin4.py
ERROR  : Failed to create the directory /var/lib/pgadmin:
           [Errno 13] Permission denied: '/var/lib/pgadmin'
HINT :   Create the directory /var/lib/pgadmin, ensure it is writeable by
         'dpage', and try again, or, create a config_local.py file
         and override the SQLITE_PATH setting per
         https://www.pgadmin.org/docs/pgadmin4/4.22/config_py.html

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Dave Page
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