Add support of changes generation. Changes will be generated (unless explicitly asked not to) automatically during check process (i.e. `repo-update --dry-run` and aliases) and uploaded to the remote server. Changes can be reviewed either by web interface or by special subcommands.
Changes will be automatically cleared during next successful build
* allow to use one application for multiple repositories
* update tests
* handle None append argument everywhere
* rewrite repository definition logic
* drop optional flags from docs
* support of new schema in systemd units
* add migration docs and ability to migrate tree automatically
* use repostory id instead
* verbose multiarchitectureerror
* object path support for s3 sync
* fix tests after rebase
By default this feature is enabled. On the first run it will copy (if
exists) databases from filesystem to local cache (one per each
architecture). Later it will use this cache for all alpm operations. In
order to update this cache, some commands (mainly package building)
provide `-y`/`--refresh` option which has same semantics as pacman -Sy
does.
Note however that due to extending `Pacman` class some methods were
renamed in order to be more descriptive:
* `Pacman.all_packages` -> `Pacman.packages`
* `Pacman.get` -> `Pacman.package_get`
This commit also adds multilib repository to the default docker image
which was missed.
