Added Backblaze B2 experimental backup support

[rez0n]

Hello, glad to offer Backblaze B2 backups support to review.
Backup function works good.
Restore function works good.
Delete function works good.

What to do in future:

1. Refactor v-add-backup-host to cloud backups support (now, this script offer only FTP parameters like HOST/USER/PASSWORD).
2. Install "python b2 module" with vesta.

Usage

1. Install python module "b2" (pip install b2)
2. Create $VESTA/conf/b2.backup.conf contains

BUCKET=<bucket_name>
B2_KEYID=<Application_Key_ID>
B2_KEY=<key>

3. Change BACKUP_SYSTEM in $VESTA/conf/vesta.conf to "local,b2" or "b2"
   Enjoy.

[justanthonylee]

I really like this one, B2 is a really low cost high performance option for backups.

[sexymeow]

Let's say you want to have daily backups, or weekly, and monthly. You can backup to 2 different buckets, making a CRON task for each one! 👍

You can do as following,

1st
Create a secondary .conf file for example: b2.backupmonthly.conf

2nd
Create new bucket and keys for that .conf
BUCKET=<bucket_name>
B2_KEYID=<Application_Key_ID>
B2_KEY=

3nd
Create monthly CLI's (just duplicate the Clis, rename them, and edit the code for the new .conf file)

Now you can create a CRON 1 to backup for 1 bucket, and CRON 2 to backup to 2 bucket, you can make one backup every 3 days, and other backup monthly for example...

Inside backblaze panel, you can select buckets and edit "Lifecycle Settings", that way it gets deleted every X days.
For example i will keep:

-every 3 days backups for 1 month (cron1);
-every month backups for 6 months (cron2);

And that's it :mrgreen: