feat: add support for S3 as external data source

[margau]

This PR adds support for S3:

• the orchestrator is a central S3 proxy
• currently, loading custom dictionaries from a S3 bucket is supported
• this can be enhanced to e.g. ipinfo parts

With S3 as alternative to local storage, Kubernetes-Like deployment (see e.g. #891) are made easier, as the components itself don't need persistent storage.

Still open:

• Documentation
• possibly more tests

[codecov]

Codecov Report

Attention: 24 lines in your changes are missing coverage. Please review.

Comparison is base (9c4ce55) 84.84% compared to head (b218267) 84.68%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
common/s3/root.go	64.44%	16 Missing ⚠️
orchestrator/clickhouse/http.go	85.18%	4 Missing ⚠️
common/schema/config.go	72.72%	3 Missing ⚠️
cmd/orchestrator.go	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #981      +/-   ##
==========================================
- Coverage   84.84%   84.68%   -0.16%     
==========================================
  Files         186      189       +3     
  Lines        7238     7322      +84     
  Branches       38       38              
==========================================
+ Hits         6141     6201      +60     
- Misses       1095     1119      +24     
  Partials        2        2              

Flag	Coverage Δ
unittests	84.68% <73.62%> (-0.16%)	⬇️

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[vincentbernat]

Note I didn't have a look as I understand this is still work in progress. Tell me when you need some comments.

[margau]

Hi,
feature-side, I'd consider this ready and would like to get a review.
The only thing missing is better test coverage, and the documentation of the final config structure.

[vincentbernat]

Sorry for taking some time. I am fine with the feature, however I have a few remarks on the implementation.

1. At first, I thought the way the configuration is split in two parts was strange. But I understand you want to reuse configuration for several dicts (or later more stuff), so ack for this.
2. There is a mechanism to handle polymorphism, take a look at use of helpers.ParametrizedConfiguration* invocations. You can then have file, http, s3, and s3mock backends. The later will use a mock version of the S3 component to avoid the Mock attribute in it. This is pretty clear in my head, if it is not for you, feel free to ignore, I'll add a commit to handle that.