Further root readme bump, factor `.clearing` content

In line with our move to `uv` and recent `nix` support update a bunch of
the summary content and factor out the order-control section to a new
`.piker.clearing` readme file with embedded todos therein.

README.rst

@@ -43,22 +43,24 @@ focus and feats:
 fitting with these tenets, we're always open to new
 framework/lib/service interop suggestions and ideas!
 
-- **100% federated**
+- **100% federated**:
   your code, your hardware, your data feeds, your broker fills.
 
-- **zero web**
+- **zero web**:
   low latency as a prime objective, native UIs and modern IPC
   protocols without trying to re-invent the "OS-as-an-app"..
 
-- **maximal privacy**: prevent brokers and mms from knowing your
-                       planz; smack their spreads with dark volume
-                       from a VPN tunnel.
+- **maximal privacy**:
+  prevent brokers and mms from knowing your planz; smack their
+  spreads with dark volume from a VPN tunnel.
 
-- **zero clutter**: modal, context oriented UIs that echew minimalism,
-                reduce thought noise and encourage un-emotion.
+- **zero clutter**:
+  modal, context oriented UIs that echew minimalism, reduce thought
+  noise and encourage un-emotion.
 
-- **first class parallelism**: built from the ground up on a next-gen
-                           structured concurrency supervision sys.
+- **first class parallelism**:
+  built from the ground up on a next-gen structured concurrency
+  supervision sys.
 
 - **traders first**: broker/exchange/venue/asset-class/money-sys agnostic