Implement a mechanism which can generate a set of customization diffs and apply them after MU

[f3flight]

by @aepifanov:
moved from adobdin/timmy#29

[f3flight]

Proposing a workflow to implement:

1. generate md5 verification (implemented)
2. for all custom packages with failed md5 verification, grab a non-custom package from the source defined in the database (not possible at the moment, need to update database structure to contain a full path to a package inside repo - currently there's only repo url and package filename which is not sufficient; also due to older packages disappearing from most recent repo after new MU release, need to always use mu-X repo symlink instead of repo with latest versions; also need to make a workaround for GA versions; finally, this will only work when internet connection is available; can make a semi-manual way - script tells which packages it needs, you download and put them in a specific folder, then re-run script with a --something parameter and it will grab packages from this folder)
3. push the packages to relevant nodes (timmy "put" functionality)
4. make a script which would unpack each package and do md5 comparison for every file inside, run it with timmy "scripts" functionality. (will need ability to reset each node's actionable attributes to avoid re-initializing NodeManager, maybe add such function in Timmy)