feat: initialize Kurdistan SDK - independent fork of Polkadot SDK

pezkuwi/roadmap/implementers-guide/src/node/utility/chain-api.md

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+# Chain API
+
+The Chain API subsystem is responsible for providing a single point of access to chain state data via a set of
+pre-determined queries.
+
+## Protocol
+
+Input: [`ChainApiMessage`](../../types/overseer-protocol.md#chain-api-message)
+
+Output: None
+
+## Functionality
+
+On receipt of `ChainApiMessage`, answer the request and provide the response to the side-channel embedded within the
+request.
+
+Currently, the following requests are supported:
+* Block hash to number
+* Block hash to header
+* Block weight
+* Finalized block number to hash
+* Last finalized block number
+* Ancestors