www/nextcloud: possible improvements to provided httpd.conf example

I value the amazing work you are doing to keep www/nextcloud in a
really good shape. Thank you for that!

I have three suggestions to possibly improve the provided httpd.conf
example:

1.) block more locations
2.) use block return 403 together with errdocs redirect
3.) only allow needed .php files

1.)
According to
https://github.com/nextcloud/server/blob/master/.htaccess#L91, 3rdparty
and lib should be blocked as well. The example already does that for
config and data.

2.)
Instead of doing "block drop", one could alternatively use "block
return 403". With an error document similar to the provided index.html
from nextcloud, a simple redirect to index.php could be provided, too,
when returning 403. This could also be done for the global server
configuration. Thus, the user would always get redirected to index.php
if he requests an invalid URL.

3.)
It seems like index.php, remote.php and status.php (potentially
cron.php for web-based cron) are the only php files which need to be
parsed by php-fpm socket via fcgi. Thus, instead of matching all php
files in the path (with "*.php*"), one could restrict php fcgi
functionality to just these three (four) files.

Change 3.) would even make change 1) unnecessary, since then there is
no danger of fetching random php files with the glob, and these block
drop could be replaced by a block drop/return 403 in the global server
configuration.

If you like these ideas, I will provide a patch.

Thanks.