Place common circuit blocks to this repository

[chiplet]

Many system blocks like the DCDC buck regulators are used in multiple projects (compute HAT and backplane). In order to facilitate design reuse it's preferable to create a library of common circuit blocks and reuse them through hierarchical sheets. When creating a repository for the circuit blocks we should decide if we want to create a dedicated repository for the circuit blocks or add them to this repository.

I think it's a better approach to add the circuit blocks to this repo for the time being for the following reasons:

• If the circuit block uses the symbol libraries in this repository it needs to add this repository as a submodule. However, if the main design also uses those symbols the library needs to either be configured through the circuit blocks repository (not very transparent), or be included in multiple places. If it exists in multiple places what happens if the two submodules go out of sync?

By adding the circuit blocks to this repository:

1. The circuit blocks would have direct access to all libraries in this repository
2. The main design would have access to the same symbols as well as the circuit blocks through this repository.

TODO

• Document this in README.md