[gc] script to perform garbage collection

It should be run inside vault

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
HEAD can be w/o tag too and should be marked as old_tag

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
gc should be done also if there are deprecated commits

Also options to force and dump

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
execute prune one more time

to ensure garbage is collected. It takes small fraction of time.

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

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
amend series of removed backups

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

commits other than anchor and outdated backup marks should be
cherry-picked

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
pretty formatting of commands

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
debug tracing of steps

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
basic rollback on the first stage of migration

tag relocation is unlikely to fail

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
allow empty commits to avoid errors in corner cases

It is safer to get empty commit than to process corner cases, proved
also by testing :)

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
parsable tracing of steps

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

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
use migrated branch to mark migration was full

So, in the case of interrupted process it should be clear is
recreation of the history was completed

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
documenting gc code generator scripts

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
removing suffix from git-vault-gc

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[vault] garbage collection action: gc

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[gc] vault-gc systemd service

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
Merge pull request #16 from deztructor/vault-gc

Garbage collection support