CI: Re-write using maintainer tools

Re-write CI using the new maintainer tools script. A few things to note:

- Put sanitizer and wasm jobs in their own scripts
- Utilize `extra_tests.sh` for additional feature combos
- We are exceeding the 20 job limit, see the README

Unless I'm made a mistake this shouldn't reduce the test coverage in any
way.

.github/workflows/README.md

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+# rust-bitcoin workflow notes
+
+We are attempting to run max 20 parallel jobs using GitHub actions (usage limit for free tier).
+
+ref: https://docs.github.com/en/actions/learn-github-actions/usage-limits-billing-and-administration
+
+The minimal/recent lock files are handled by CI (`rust.yml`).
+
+## Jobs
+
+Run from `rust.yml` unless stated otherwise. Total 21 jobs but
+`Prepare` is quick and must be run first anyway.
+
+0.  `Prepare`
+1.  `Stable - minimal`
+2.  `Stable - recent`
+3.  `Nightly - minimal`
+4.  `Nightly - recent`
+5.  `MSRV - minimal`
+6.  `MSRV - recent`
+7.  `Lint`
+8.  `Docs`
+9.  `Docsrs`
+10. `Bench`
+11. `Format`
+12. `ASAN`
+13. `Arch32Bit`
+14. `WASM`
+15. `NoStd`
+<!-- Jobs run from `cross.yaml` -->
+16. `Cross testing - aarch64-unknown-linux-gnu`
+17. `Cross testing - i686-unknown-linux-gnu`
+18. `Cross testing - x86_64-pc-windows-gnu`
+19. `Cross testing - x86_64-unknown-linux-gnu`
+20. `Cross testing - aarch64-unknown-linux-musl`
+21. `Cross testing - arm-unknown-linux-gnueabi`
+22. `Cross testing - arm-unknown-linux-gnueabihf`
+23. `Cross testing - armv7-unknown-linux-gnueabihf`
+24. `Cross testing - powerpc-unknown-linux-gnu`
+25. `Cross testing - powerpc64le-unknown-linux-gnu`
+26. `Cross testing - riscv64gc-unknown-linux-gnu`
+27. `Cross testing - s390x-unknown-linux-gnu`
+28. `Cross testing - x86_64-unknown-linux-musl`

.github/workflows/cron-semi-weekly-update-nightly.yml

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+name: Update Nightly rustc
+on:
+  schedule:
+    - cron: "0 0 * * 1,4" # runs every Monday and Thursday at 00:00
+  workflow_dispatch: # allows manual triggering
+jobs:
+  format:
+    name: Update nightly rustc
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@nightly
+      - name: Update rust.yml to use latest nightly
+        run: |
+          set -x
+          # Not every night has a nightly, so extract the date from whatever
+          # version of the compiler dtolnay/rust-toolchain gives us.
+          NIGHTLY_DATE=$(rustc +nightly --verbose --version | sed -ne 's/^commit-date: //p')
+          # Update the nightly version in the reference file.
+          echo "nightly-${NIGHTLY_DATE}" > nightly-version
+          echo "nightly_date=${NIGHTLY_DATE}" >> $GITHUB_ENV
+          # Some days there is no new nightly. In this case don't make an empty PR.
+          if ! git diff --exit-code > /dev/null; then
+              echo "Updated nightly. Opening PR."
+              echo "changes_made=true" >> $GITHUB_ENV
+          else
+              echo "Attempted to update nightly but the latest-nightly date did not change. Not opening any PR."
+              echo "changes_made=false" >> $GITHUB_ENV
+          fi
+      - name: Create Pull Request
+        if: env.changes_made == 'true'
+        uses: peter-evans/create-pull-request@v6
+        with:
+          token: ${{ secrets.APOELSTRA_CREATE_PR_TOKEN }}
+          author: Update Nightly Rustc Bot <[email protected]>
+          committer: Update Nightly Rustc Bot <[email protected]>
+          title: Automated daily update to rustc (to nightly-${{ env.nightly_date }})
+          body: |
+           Automated update to Github CI workflow `rust.yml` by [create-pull-request](https://github.com/peter-evans/create-pull-request) GitHub action
+          commit-message: Automated update to Github CI to rustc nightly-${{ env.nightly_date }}
+          branch: create-pull-request/daily-nightly-update