Add docs on creating service (#822)

* Add docs on creating service

* Add more docs about ooni services setup

* Improvements to docs

README.md

@@ -1,17 +1,3 @@
 # OONI backend
 
 Welcome to the OONI backend!
-
-We follow the principles of a building a [12 factor app](https://12factor.net/),
-which can be summarized as:
-
-- Use declarative formats for setup automation, to minimize time and cost for
-  new developers joining the project;
-- Have a clean contract with the underlying operating system, offering maximum
-  portability between execution environments;
-- Are suitable for deployment on modern cloud platforms, obviating the need for
-  servers and systems administration;
-- Minimize divergence between development and production, enabling continuous
-  deployment for maximum agility;
-- And can scale up without significant changes to tooling, architecture, or
-  development practices.

ooniapi/README.md

@@ -4,56 +4,3 @@ Welcome to the new OONI API!
 
 This is still work in progress, but the end goal is to eventually reach feature
 parity with backend/api/ (aka legacy flask based API).
-
-The general idea is to break OONI API components into smaller pieces that can
-be more easily deployed and managed without worrying too much about the blast
-radius caused by the deployment of a larger component.
-
-To this end, we divide the OONI API sub-components into what we call
-"services".
-
-Each service (found in the `ooniapi/services` folder) should have a narrowly
-defined scope. It's optimal to slice services up depending on how critical they
-are (tier0, tier1, tier2) and what kinds of resources they need to access
-(databases, object store, specific hosts, etc.).
-
-There is also a `common` folder for all shared logic common to every component.
-
-## List of OONI API Services
-
-### Tier0
-
-- `ooniprobe`, (aka `probe_services`), where probes send their measurements and
-  get metadata to run experiments;
-- `oonirun`, CRUD for editing OONI Run links, but also for probes to get the
-  descriptors and run tests (this fact is what makes it tier0);
-- `prioritization`, CRUD for editing the priorities of URLs and populating the
-  appropriate clickhouse tables so they can be used by probe;
-- `fastpath`, responsible for taking measurements blobs sent to `ooniprobe`
-  service and storing them in s3;
-
-### Tier1
-
-- `data`, (aka OONI Data Kraken), where Explorer and other clients access the
-  observations data and experiment results;
-- `findings`, (aka `incidents`) backend for findings pages on explorer;
-- `measurements`, backend for aggregation and list measurement endpoints (note
-  also probe uses this, so it's maybe on the high end of tier1);
-- ``
-
-### Tier2
-
-- `testlists`, for proposing changes to the test-lists and submitting a github PR;
-
-## Developer setup
-
-We use `hatch` for managing development environments. Once you have [installed
-hatch](https://hatch.pypa.io/1.9/install/), check the `Makefile` for service
-specific commands.
-
-Generally it should work something like:
-
-```
-make test
-make run
-```