V15/task/cleanup obsolete (#17433)

* Replace obsolete UserGroup Alias consts to key equivalent in tests

* Update use of usergroup alias consts to key equivalent in IsSystemgroup extension method

* Obsolete (internally) unused helper function which purpose doesn't even seem true

* Prepped EmbedProviders for proper removal of non async methods and unneeded proxy methods

* Remove obsoleted UmbracoPath and updated internal references

* Corrected  mistake and updated unittets

* Update usergroup tests that use aliases for "system" groups

* Replace more uses of globalsettings.UmbracoPath

* Remove GetDateType by key non async

* Cleanup some usages of hostingEnvironment.MapPathContentRoot

* More easy obsoletion cleanup

* Small Typeload cleanup

* More obsolete removal

* Deploy obsoletion cleanup

* Remove obsolete methods from OEmbedProviderBase.cs

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Co-authored-by: Zeegaan <skrivdetud@gmail.com>

src/Umbraco.Core/Configuration/Models/SecuritySettings.cs

@@ -95,13 +95,6 @@ public class SecuritySettings
     [DefaultValue(StaticUserDefaultLockoutTimeInMinutes)]
     public int UserDefaultLockoutTimeInMinutes { get; set; } = StaticUserDefaultLockoutTimeInMinutes;
 
-    /// <summary>
-    /// Gets or sets a value indicating whether to allow editing invariant properties from a non-default language variation.
-    /// </summary>
-    [Obsolete("Use ContentSettings.AllowEditFromInvariant instead")]
-    [DefaultValue(StaticAllowEditInvariantFromNonDefault)]
-    public bool AllowEditInvariantFromNonDefault { get; set; } = StaticAllowEditInvariantFromNonDefault;
-
     /// <summary>
     ///     Gets or sets a value indicating whether to allow concurrent logins.
     /// </summary>