Add default_character_set options to mysql helpers

[Thatoo]

Update ynh_mysql_connect_as() helper to be able, when restoring a database, to specify --default-character-set="xxx", xxx being latin1 or utf8mb4

The problem

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Solution

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PR Status

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How to test

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[alexAubin]

Can you elaborate on the motivation behind this exactly ?

[Thatoo]

Creating Dokos package, I need to be sure all character in database are in utf8mb4
So I copied what nextcloud does and then I thought that if nextcloud needs it and Dokos also, maybe other package maintainer might need it too.
https://github.com/YunoHost-Apps/nextcloud_ynh/blob/master/scripts/_ynh_mysql_connect_as.sh
and extract from install script :

# Set the user as admin
ynh_mysql_connect_as --user=$db_name --password="$db_pwd" --database=$db_name --default_character_set="utf8mb4" \
    <<< "INSERT INTO oc_group_user VALUES ('admin','$admin');"
# And delete admin user
exec_occ user:delete admin