add encointer runtime (polkadot-fellows#80)

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In fulfillment of
[RFC22](https://github.com/polkadot-fellows/RFCs/blob/main/text/0022-adopt-encointer-runtime.md),
this PR adds the encointer runtime.

replacing polkadot-fellows#17 

notes
* this runtime shall enable async backing at the conservative 12s block
time ("Phase 1" in Santi's tutorial). in a subsequent step we shall set
target block rate of 6s
* We used the same upstream dependency versions like the other system
chains on master
* The PR includes the runtime's commit history for reference
* strictly using published crates.io dependencies

---------

Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: Cecile Tonglet <[email protected]>
Co-authored-by: Sergei Shulepov <[email protected]>
Co-authored-by: Shawn Tabrizi <[email protected]>
Co-authored-by: Joshy Orndorff <[email protected]>
Co-authored-by: Shaun Wang <[email protected]>
Co-authored-by: Andrew Jones <[email protected]>
Co-authored-by: Vincent Geddes <[email protected]>
Co-authored-by: Sebastian Thiel <[email protected]>
Co-authored-by: Keith Yeung <[email protected]>
Co-authored-by: Gavin Wood <[email protected]>
Co-authored-by: Robert Habermeier <[email protected]>
Co-authored-by: Amar Singh <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: Guillaume Thiolliere <[email protected]>
Co-authored-by: Alexander Popiak <[email protected]>
Co-authored-by: André Silva <[email protected]>
Co-authored-by: clangenb <[email protected]>
Co-authored-by: Christian Langenbacher <[email protected]>
Co-authored-by: anizeani <[email protected]>
Co-authored-by: mosonyi <[email protected]>
Co-authored-by: NicJak <[email protected]>
Co-authored-by: pifragile <[email protected]>
Co-authored-by: Joakim Nyman <[email protected]>
Co-authored-by: Kutsal Kaan Bilgin <[email protected]>
Co-authored-by: Paulo Martins <[email protected]>
Co-authored-by: tugy <[email protected]>
Co-authored-by: Milos Kriz <[email protected]>
Co-authored-by: Szilárd Parrag <[email protected]>
Co-authored-by: joe petrowski <[email protected]>

.github/workflows/runtimes-matrix.json

@@ -53,5 +53,12 @@
     "path": "system-parachains/collectives/collectives-polkadot",
     "uri": "wss://polkadot-collectives-rpc.polkadot.io:443",
     "is_relay": false
+  },
+  {
+    "name": "encointer-kusama",
+    "package": "encointer-kusama-runtime",
+    "path": "system-parachains/encointer",
+    "uri": "wss://kusama.api.encointer.org:443",
+    "is_relay": false
   }
 ]

CHANGELOG.md

@@ -4,6 +4,11 @@ Changelog for the runtimes governed by the Polkadot Fellowship.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+
+### Added
+- Add [Encointer](https://encointer.org) system parachain runtime, completing [RFC22](https://github.com/polkadot-fellows/RFCs/blob/main/text/0022-adopt-encointer-runtime.md) ([polkadot-fellows/runtimes#80](https://github.com/polkadot-fellows/runtimes/pull/80))
+
 ## [1.1.0] 10.01.2024
 
 ### Changed