readme: update and split into various parts

examples/README.md

@@ -0,0 +1,59 @@
+Examples
+---
+
+The easiest way to try out nix-bitcoin is to use one of the provided examples.
+
+```bash
+git clone https://github.com/fort-nix/nix-bitcoin
+cd nix-bitcoin/examples/
+nix-shell
+```
+
+The following example scripts set up a nix-bitcoin node according to [`configuration.nix`](configuration.nix) and then
+shut down immediately. They leave no traces (outside of `/nix/store`) on the host system.\
+By default, [`configuration.nix`](configuration.nix) enables `bitcoind` and `clightning` (with an onion service).
+
+- [`./deploy-container.sh`](deploy-container.sh) creates a [NixOS container](https://github.com/erikarvstedt/extra-container).\
+  This is the fastest way to set up a node.\
+  Requires: [Nix](https://nixos.org/), a systemd-based Linux distro and root privileges
+
+- [`./deploy-qemu-vm.sh`](deploy-qemu-vm.sh) creates a QEMU VM.\
+  Requires: [Nix](https://nixos.org/nix/)
+
+- [`./deploy-nixops.sh`](deploy-nixops.sh) creates a VirtualBox VM via [NixOps](https://github.com/NixOS/nixops).\
+  NixOps can be used to deploy to various other backends like cloud providers.\
+  Requires: [Nix](https://nixos.org/nix/), [VirtualBox](https://www.virtualbox.org)
+
+- [`./deploy-container-minimal.sh`](deploy-container-minimal.sh) creates a
+  container defined by [minimal-configuration.nix](minimal-configuration.nix) that
+  doesn't use the [secure-node.nix](../modules/presets/secure-node.nix) preset.
+  Also shows how to use nix-bitcoin in an existing NixOS config.\
+  Requires: [Nix](https://nixos.org/), a systemd-based Linux distro and root privileges
+
+Run the examples with option `--interactive` or `-i` to start a shell for interacting with
+the node:
+```bash
+./deploy-qemu-vm.sh -i
+```
+
+### Tests
+The internal test suite is also useful for exploring features.\
+The following `run-tests.sh` commands leave no traces (outside of `/nix/store`) on
+the host system.
+
+```bash
+git clone https://github.com/fort-nix/nix-bitcoin
+cd nix-bitcoin/test
+
+# Run a Python test shell inside a VM node
+./run-tests.sh debug
+print(succeed("systemctl status bitcoind"))
+
+# Run a node in a container. Requires systemd and root privileges.
+./run-tests.sh container
+c systemctl status bitcoind
+
+# Explore a single feature
+./run-tests.sh --scenario electrs container
+```
+See [`run-tests.sh`](../test/run-tests.sh) for a complete documentation.