Update docs: Frosting now supports configuration

[devlead]

Frosting has since a year back now configuration support, so docs should be updated i.e. this removed

https://github.com/cake-build/website/blob/9ca63c9fcb8bdcda8f5f522aa076046a957fbef2/input/docs/running-builds/configuration/set-configuration-values.md?plain=1#L8

https://github.com/cake-build/website/blob/9ca63c9fcb8bdcda8f5f522aa076046a957fbef2/input/docs/running-builds/configuration/default-configuration-values.md?plain=1#L9

And examples added using

public static CakeHost UseCakeSetting(this CakeHost host, string key, string value)

i.e.

Show Process Command Line in frosting would atm be (maybe should add a helper method here like tool path🤔)

cakeHost.UseCakeSetting("settings_showprocesscommandline", bool.TrueString)

Tools Path would be

cakeHost.SetToolPath("./tools")

Would need some investigation as all settings aren't applicable i.e. Skip Verification, Addin NuGet Dependencies, and Addins Path are useful in scripting only.

Config file, environment variables, and command-line arguments should work just as in Cake.Tool as FrostingConfiguration uses CakeConfigurationProvider under the hood.