[bin] executable the-vault in bin

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[config] support for service files

service files has special prefix (md5 of the-vault :)), so they can be
identified and processed in a special way

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[unit] new configuration format, versioning

New configuration format adds ability to work with multiply items,
versioning, so, the only non-versioned version is the previous one,
called 0 :) Also it cares about symlinks set as backup items

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[tests] for the vault/unit

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[unit] fix in old unit format fallback

And test for correct support

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[unit] support for plain path items

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>