build(cmake)!: Add support for installation and usage as a library in other CMake projects; Add example project to test this use case.

[PacificViking]

Description

Previously, users of ystdlib needed to use it through add_subdirectory. This PR updates ystdlib to allow installing selected ystdlib libraries and using them through find_package.

When building ystdlib the user can define the CMake variable ystdlib_LIBRARIES with a semicolon separated list of ystdlib library names to build (if omitted all libraries are built). Then when cmake --install is run all built libraries will be installed and configured to work with find_package.

For ystdlib_LIBRARIES, if a user lists a ystdlib library that depends on another ystdlib not listed that dependent library will be added to the list and built.

This PR also adds an examples/ directory containing an example CMake project to:

1. show users how to use ystdlib in their CMake project.
2. test a CMake project can successfully use an installation of ystdlib.

Support for using COMPONENTS with find_package to selectively depend on (installed) libraries is deferred to a future PR.

This PR sets the minimum version of CMake to 3.23 to add support for FILE_SETS.

Checklist

• The PR satisfies the [contribution guidelines][yscope-contrib-guidelines].
• This is a breaking change and that has been indicated in the PR title, OR this isn't a
  breaking change.
• Necessary docs have been updated, OR no docs need to be updated.

Validation performed

Test cases still pass. Example builds and passes by manually running the following commands:

cmake -S . -B build/
cmake --build build/
cmake --install "./build" --prefix "./build/examples/ystdlib
cmake -S "./examples" -B "./build/examples" -Dystdlib_ROOT="./build/examples/ystdlib"
cmake --build build/examples/
./build/examples/linking-tests


[yscope-contrib-guidelines]: https://docs.yscope.com/dev-guide/contrib-guides-overview.html


<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
	- Added example programs and documentation demonstrating how to link and use all ystdlib library components.
	- Introduced comprehensive CMake installation and package configuration support, enabling `find_package(ystdlib)` integration.
	- Added new CMake helper scripts for streamlined library creation, testing, and installation.

- **Enhancements**
	- Unified build and variable naming conventions across CMake files for consistency.
	- Made the set of libraries to build configurable via a single variable.
	- Improved modularity and clarity in build configuration for all library components.
	- Updated minimum CMake version requirement to 3.23.
	- Replaced Boost dependency handling with refined package find commands.

- **Bug Fixes**
	- Prevented duplicate target definitions in build scripts.

- **Documentation**
	- Updated and expanded README files with installation, usage, and testing instructions.

- **Chores**
	- Updated build, lint, and task configuration files to reflect new structure and naming.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->