Template dans .env

Comme mentionné par @daxid, les variable host, user, ftppass et encpass ne sont pas toujours très clair, j'ai donc ajouté un commentaire pour chaque afin de spécifier leur utilité.

Closes #2 (closed)

.env.sample

+# FTP host (the storage box adresses for Tetras)
 host="CHANGEME"
+# The FTP user (or sub user for Tetras)
 user="CHANGEME"
+# FTP password (give at creation of subuser at Tetras) /!\ to put in the password manager
 ftppass="CHANGEME"
+# Generetade random string /!\ to put in the password manager
 encpass='CHANGEME'
 
 bckplist="/root /etc /srv /var/www /usr /lib /opt /var/opt /var/lib/docker/volumes/ /home"
@@ -16,6 +20,7 @@ BK_FULL_FREQ="3W" # create a new full backup every...
 BK_FULL_LIFE="2M" # delete any backup older than this
 BK_KEEP_FULL="2"  # How many full+inc cycle to keep
 
+# Script for backup
 pre_actions(){
     if [ ! -z "$(which mysql)" ]; then
         mysqldump --events --single-transaction --flush-logs --all-databases  --default-character-set=utf8 \