Add a reference to Pocket Pruner (#1572)

## Description

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### Summary generated by Reviewpad on 14 Jul 23 15:36 UTC
This pull request adds a reference to Pocket Pruner in the README.md file. It also includes a new document, pruner.md, which provides information about the Pocket Pruner tool and how to use it for servicers and validators. Additionally, it includes contact information for C0D3R support regarding any pruner-related issues.
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README.md

@@ -77,6 +77,10 @@ For more detailed command information, see the [usage section](doc/specs/cli/).
 
 Snapshots are provided by [Liquify LTD](https://www.liquify.io/) details on how to access the snapshots can be found in [snapshot.md](doc/guides/snapshot.md)
 
+## Pocket Pruner
+
+An offline pruning tool is provided by [C0D3R](https://c0d3r.org/). The tool is available in [their GitHub repository](https://github.com/msmania/pocket-pruner/).
+
 ## Accessing TestNet
 
 TestNet information can be found at [testnet.md](doc/guide/testnet.md)

doc/guides/pruner.md

@@ -0,0 +1,8 @@
+# Pocket Pruner
+
+C0D3R provides [a pruning tool](https://github.com/msmania/pocket-pruner/) for Pocket Network.
+You can use it for your servicers and validators.  Do not prune a node that is
+pointed as a RelayChain endpoint in chains.json.
+
+For any pruner related issues, please contact [C0D3R support](mailto:support@@c0d3r.org)
+or [their discord channel](https://discord.com/channels/1067167998416269353/1070255553265274910).