Selenium 4 upgrade

[jamesmcroft]

Resolves #193

This change introduces an upgrade to Selenium 4, utilizing Appium's 5.0.0 release candidate packages for cross-platform native application support.

With the update of the libraries, various changes have been made to match the new API layers provided by both Selenium 4 and Appium. This includes:

• Remove platform specific elements and replacing with generic WebElement
• Update references to platform specific drivers to remove generic implementation with platform specific elements
• Support for .NET 6 (minimum) through 8 as stipulated by Appium

No major API changes have been introduced in this change, in theory, resulting in a seamless upgrade from previous Legerity versions. This does require validation on our part though.

Not all platforms have been thoroughly tested with these changes and this is also required on our part.

PR checklist

Coding

• Run code styling rules on all new source file changes

Documentation

• Add/update articles in docs to support new source file changes (if required)
• Document major breaking changes (if required)

Tooling

• Add/update support for platform specifics in the PageObjectGenerator (if required)
• Add/update .NET project templates to support new source file changes (if required)

Testing

• Add/update sample tests for source file changes
• Run tests locally and validate pass

Other Tasks

• Validate no breaking changes with a preview release for an in-production workload

Other information