docs: New README, two options to choose from right now (#59)

Reviewed-on: #59
Co-authored-by: Jean-Gabriel Gill-Couture <jg@nationtech.io>
Co-committed-by: Jean-Gabriel Gill-Couture <jg@nationtech.io>

harmony_cli/README.md

@@ -0,0 +1,27 @@
+## Quick demo
+
+`cargo run -p example-tui`
+
+This will launch Harmony's minimalist terminal ui which embeds a few demo scores.
+
+Usage instructions will be displayed at the bottom of the TUI.
+
+`cargo run --bin example-cli -- --help`
+
+This is the harmony CLI, a minimal implementation
+
+The current help text:
+
+```
+Usage: example-cli [OPTIONS]
+
+Options:
+  -y, --yes              Run score(s) or not
+  -f, --filter <FILTER>  Filter query
+  -i, --interactive      Run interactive TUI or not
+  -a, --all              Run all or nth, defaults to all
+  -n, --number <NUMBER>  Run nth matching, zero indexed [default: 0]
+  -l, --list             list scores, will also be affected by run filter
+  -h, --help             Print help
+  -V, --version          Print version```
+