Retention policy

[stalkerg]

• recycle
• changes in the retention period
• meta information about period
• special command for changes retention period

We want set up special rules for each backup for automatic removal.

[za-arthur]

Retention policy is done by retention purge command with redundancy and window parameters.

[stalkerg]

I think test does not check all cases.

[za-arthur]

Retention cases? Will think about it.

[za-arthur]

Tests were added.