Allow removal of prefix when proxying to another server (#630) (#924)

* #630 Allow removal of prefix when proxying to another server

* #630 Rename replace to replace settings and ensure properties used in place of fields

* #630 Update replace settings type name to ProxyUrlReplaceSettings

* #630 Add admin model and update settings parser to parse new values

* Fix formatting issues

* #630 Ensure json mapping between admin model and internal model takes place

* #630 Refactor parsing and structure of extracting new proxy url

* Reduce function complexity

* #630 Fix line length issues and remove try prefix from parser methods

src/WireMock.Net.Abstractions/Admin/Settings/ProxyUrlReplaceSettingsModel.cs

@@ -0,0 +1,18 @@
+namespace WireMock.Admin.Settings;
+
+/// <summary>
+/// Defines an old path param and a new path param to be replaced when proxying.
+/// </summary>
+[FluentBuilder.AutoGenerateBuilder]
+public class ProxyUrlReplaceSettingsModel
+{
+    /// <summary>
+    /// The old path value to be replaced by the new path value
+    /// </summary>
+    public string OldValue { get; set; } = null!;
+
+    /// <summary>
+    /// The new path value to replace the old value with
+    /// </summary>
+    public string NewValue { get; set; } = null!;
+}