Merge bitcoin/bitcoin#24352: Add doc/design/libraries.md

dc1e7ad7a5 Add doc/design/libraries.md (Ryan Ofsky)

Pull request description:

  Prompted by the [libbitcoinkernel issue #24303](https://github.com/bitcoin/bitcoin/issues/24303) and PRs, I started looking at  existing libraries and what their dependencies are and wrote this document to describe them and where `libbitcoinkernel` fits in.

  Readable link is:  https://github.com/ryanofsky/bitcoin/blob/pr/libs/doc/design/libraries.md

  Feedback is welcome

ACKs for top commit:
  laanwj:
    ACK dc1e7ad7a5
  hebasto:
    Approach ACK dc1e7ad7a5, using this doc as a guide in https://github.com/hebasto/bitcoin/pull/3 :)

Tree-SHA512: 7687b1847797c50de1f5ea721bd201cc8304690064743fbe6d69e2198cc239084e9da7d158be65bea948a6ec3d71d74c84122c0e523c390b389b49ea8d2cddc9

doc/README.md

@@ -64,6 +64,7 @@ The Bitcoin repo's [root README](/README.md) contains relevant information on th
 - [BIPS](bips.md)
 - [Dnsseed Policy](dnsseed-policy.md)
 - [Benchmarking](benchmarking.md)
+- [Internal Design Docs](design/)
 
 ### Resources
 * Discuss on the [BitcoinTalk](https://bitcointalk.org/) forums, in the [Development & Technical Discussion board](https://bitcointalk.org/index.php?board=6.0).
@@ -71,7 +72,6 @@ The Bitcoin repo's [root README](/README.md) contains relevant information on th
 
 ### Miscellaneous
 - [Assets Attribution](assets-attribution.md)
-- [Assumeutxo design](assumeutxo.md)
 - [bitcoin.conf Configuration File](bitcoin-conf.md)
 - [CJDNS Support](cjdns.md)
 - [Files](files.md)