Remove deprecated Redux package and RTK example app (#73)

This PR removes all Redux-specific support from the repo now that
@trrack/redux is no longer supported.

It deletes the packages/redux workspace and the apps/rtk-trrack-example
example app, updates root workspace scripts so build/test/lint
automation only targets @trrack/core, removes now-unused root
dependencies like react-redux, refreshes yarn.lock, and updates the
README to reflect the new repo structure.

## Why

Redux support is deprecated and should no longer be shipped, exercised
in CI, or documented as part of the active workspace.

## Changes

- Remove packages/redux
- Remove apps/rtk-trrack-example
- Update root package.json scripts to stop building/testing/linting
Redux
- Remove unused root Redux-related dependencies
- Refresh yarn.lock
- Update README repo structure/docs

Author: JackWilb

README.md

@@ -52,11 +52,9 @@ trrack-monorepo
 |
 |--- pacakges # trrack library is located in this folder
     |--- core # Core action-based tracking library
-    |--- redux # Redux toolkit wrapper for core
 |
 |--- apps # Trrack examples are located in this folder
     |--- react-trrack-example
-    |--- rtk-trrack-example
 ```
 
 Following the standards for Nx monorepos please install any dependency for the applications directly to root workspace. This ensures all the applications use same versions of any dependency. For the packages, install the dependency to appropriate package.