refactor: ADR - Move Rosetta to standalone repository

docs/architecture/adr-066-rosetta-standalone.md

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+# ADR 606: Rosetta standalone
+
+## Changelog
+
+* May 31, 2023: Initial draft (@Bizk)
+
+## Status
+
+DRAFT
+
+## Abstract
+
+Rosetta implementation runs on top of Cosmos SDK. The tool should rely on stable cosmos-sdk.
+releases and not experimental features in order to ensure usability and stability.
+Having the tool inside the main cosmos-sdk repo may cause unrequired updates, and make the
+tool maintenance more complicated.
+
+## Context
+
+In the current context; Rosetta is inside cosmos-sdk project due to easier maintainability.
+This is a problem because as seen in some previous commits, it has suffered unrequired changes
+like updates due to a refactor or a new experimental feature. Such changes can cause mismatches 
+in dependencies, or unexpected behaviour that needs to be addressed down the line.
+
+Since Rosetta is a standalone tool that has been implemented using Cosmos-sdk, it should 
+rely only on each release, instead of being affected by experimental features or
+interfeering over the cosmos-sdk development.
+
+Decoupling Rosetta from the cosmos-sdk project is not only a good practice since it keeps the
+scope well defined, but also it ensures better maintainability over time.
+
+## Alternatives
+
+The 2 altnernatives are:
+- **Keep Project inside Cosmos-sdk**: This might be easier to handle from a fully immersed position.
+  maintainer's point of view, who works on different aspects of cosmos-sdk and might want to try
+  features into Rosetta.
+- **Move the project into another repo**: This approach intends to keep the scope well defined,
+  and to ensure maintainability and stability over time.
+
+## Decision
+
+We will move Rosetta into a standalone repo in order to keep the Scope well defined, a stable
+versioning, and to ensure an easier and cleaner maintainability.
+
+We will also add and keep track of quality standards as tests and follow cosmos-sdk releases.
+
+## Consequences
+
+The consequence will be a new repo that contains the rosetta tool implemented by cosmos.
+
+### Positive
+
+- Better scope.
+- Easier miantainability and testing.
+- Avoids unrequired changes.
+- Easier to fork / contribute.
+
+### Negative
+
+- Adds one more repo to keep track of.
+- More dificult to test experimental features from cosmos-sdk
+
+## Further Discussions
+
+- [Discussion on migrating Rosetta into a standalone repo](https://github.com/cosmos/cosmos-sdk/issues/16276)
+- [Zondax plugin implementation Test](https://github.com/Zondax/cosmos-sdk/pull/653)