stack/erp5: Fix NEO URL formatting for WCFS

The NEO/go commit kirr/neo@8c974485
changed the URL with which a NEO/go client can be loaded from

    // neo://name@master1,master2,...,masterN?options

to

    neo(s)://[credentials@]master1,master2,...,masterN/name?options

We need to apply this change in the NEO URL structure to instance-wcfs.cfg.in
to use WCFS with NEO storage.

Why?
====

The URL in instance-wcfs.cfg.in is finally send to wcfs binary, which
will open a NEO/go client with this URL via the "openClientByURL" function [1].
If the URL formatting instance-wcfs.cfg.in follows the old pattern,
NEO/go is unable to create a NEO/go client and may even raise an
exception [2], because information regarding NEO server is at the wrong
position of the URL.

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[1] See https://lab.nexedi.com/kirr/neo/blob/87199da2b163c09ed3946b7ab9bb00a5b987d377/go/neo/client.go#L416-534
for openClientByURL.

[2] For instance when using the old pattern of putting the cluster name
in the "user" part, NEO/go will raise "credentials can be specified only
with neos:// scheme", because NEO/go reserves the "user" part for
encryption information,
see https://lab.nexedi.com/kirr/neo/blob/87199da2b163c09ed3946b7ab9bb00a5b987d377/go/neo/client.go#L449

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/reviewed-by @kirr
/reviewed-on !1307