Update external_storage_configuration_gui.rst

[joshmorel]

To resolve #1925

@skjnldsv This updates the screenshots to remove Dropbox etc - it definitely applies back to 16. Not sure about 15.

I noticed "Mount options" is also quite different with v16+ so I changed that in the 2nd commit of this PR:

Nothing else seemed too different (some screenshots with older design but similar enough) however maybe a quick look through by the main person responsible for with apps/files_external might be worthwhile?

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[skjnldsv]

Ah wait, we merged a bit too fast ^^'

@joshmorel where are your new images used in the docs? I don't see any reference so far?

[joshmorel]

@skjnldsv

All the new images - are replacing existing files referenced in:

https://github.com/nextcloud/documentation/blob/master/admin_manual/configuration_files/external_storage_configuration_gui.rst

Lines:
33: .. figure:: external_storage/images/add_storage.png
91: .. figure:: external_storage/images/mount_options.png
131: .. figure:: external_storage/images/user_mounts.png

[skjnldsv]

Ah sorry, I misunderstood github, I thought those were new files, not modified ones! All good! 😁
Thanks a lot for this!

[joshmorel]

@skjnldsv

NP. Like #1891 this can be backported to v16. I supposed to call those slash commands as the contributor or you as the maintainer?

[skjnldsv]

@joshmorel you can also do it by commenting like this

/backport to stable18

[skjnldsv]

/backport to stable17

[skjnldsv]

/backport to stable16

[backportbot-nextcloud]

backport to stable18 in #1928

[backportbot-nextcloud]

backport to stable17 in #1929

[backportbot-nextcloud]

backport to stable16 in #1930