[top_darjeeling] ECDSA enablement

@sameo is already working on this.

Since Jun 4, 2024.

## Problem Statement

Darjeeling still relies on RSA and SPHINCS for signature verification and attestation.

For security reasons and for saving ROM and OTP space, Earlgrey, from the `master` branch, switched to ECDSA (p256 and p384) and dropped RSA entirely.

Darjeeling should also initiate that migration from RSA to ECDSA.

## Plan

There are several components that must be synced from `master` in order to fully support ECDSA and drop RSA:

1. `hw/ip/otbn`: The ECDSA operations (attestation and verification) are offloaded to OTBN and thus we need to sync this subsystem from `master`
2. `sw/otbn`: All the crypto implementation for ECDSA lives there and must be updated.
3. `silicon_creator/sigverify`: The signature verification API and framework now supports ECDSA in `master`.
4. `silicon_creator/otbn_boot_services`: The OTBN operations for secure boot (attestation and verification) have been abstracted into a boot services API.
5. `sw/host/opentitan{tool,lib}`: The host tools in `master` support generating ECDSA keys and signing payloads with those keys

Additionally, the `rom_patch` API should use the boot services to verify ROM patches signatures, and the documentation should be updated accordingly (switch from RSA signatures).

## Steps

* [x] https://github.com/lowRISC/opentitan/issues/23477
* [x] https://github.com/lowRISC/opentitan/issues/23478
* [x] https://github.com/lowRISC/opentitan/issues/23479
* [ ] https://github.com/lowRISC/opentitan/issues/23481
* [ ] https://github.com/lowRISC/opentitan/issues/23482
* [ ] https://github.com/lowRISC/opentitan/issues/23483
* [ ] https://github.com/lowRISC/opentitan/issues/23484
* [ ] https://github.com/lowRISC/opentitan/issues/23485