Replicated service and reproducible patch archives

@legeana is already working on this.

Since Jan 26, 2020.

We can host multiple instances of the service provided that they are able to catch up with the main replica on their own. For this we need to be able to generate exactly same zip files
- https://wiki.debian.org/ReproducibleBuilds/TimestampsInZip
- We can use revision commit timestamp for all files, thanks @textshell for suggestion

Snippet of python code how we can do it:
```python
import zipfile

with zipfile.ZipFile('/tmp/test.zip', 'w') as z:
f = zipfile.ZipInfo()
f.filename = 'hello.txt'
f.date_time = (1980, 1, 1, 0, 0, 0)
f.compress_type = zipfile.ZIP_DEFLATED
z.writestr(f, 'hello world')
f = zipfile.ZipInfo()
f.filename = 'world.txt'
f.date_time = (1980, 1, 1, 0, 0, 0)
f.compress_type = zipfile.ZIP_DEFLATED
z.writestr(f, 'hello big world')
```