OPDS Support (#526)

* Added some basic OPDS implementation

* Fixed an issue with feed href

* More changes

* Added library routes and moved user code to a method so we can hack in fixed code without authentication

* Images now load on the OPDS reusing our existing Image infrastructure.

* Added the ability to download and moved some download code to a dedicated service

* Download is working, pagination is implemented.

* Refactored libraries to use pagination

* Laid foundation for OpenSearch implementation

* Fixed up some serialization issues and some old code that wasn't referencing helper methods

* Ensure chapters are sorted when we send them over OPDS

* OpenSearch implemented

* Removed any support for OPDS-PS due to lack of apps supporting it.

* Don't distribute development.json nor stats directory on build.

* Implemented In Progress feed as well.

* Ability to enable OPDS for server. OPDS now accepts initial call as POST in case app uses username/password.

* UI now properly renders state for OPDS enablement. Added Collections routes.

* Fixed pagination startIndex on OPDS feeds when there is less than 1 page.

* Chunky Reader now works. It only accepts UTF-8 encodings

* More Chunky fixes

* More chunky changes, such a fussy client.

* Implemented the ability to have a custom api key assigned to a user and use that api key as your authentication token against OPDS routing.

* Implemented the ability to reset your API Key

* Fixed favicon not being sent back correctly

* Fixed an issue where images wouldn't send on OPDS feed.

* Implemented Page streaming and fixed a pagination bug

* Hooked in the ability to save progress in Kavita when Page Streaming

API/DTOs/OPDS/OpenSearchDescription.cs

@@ -0,0 +1,42 @@
+using System.Xml.Serialization;
+
+namespace API.DTOs.OPDS
+{
+    [XmlRoot("OpenSearchDescription", Namespace = "http://a9.com/-/spec/opensearch/1.1/")]
+    public class OpenSearchDescription
+    {
+        /// <summary>
+        /// Contains a brief human-readable title that identifies this search engine.
+        /// </summary>
+        public string ShortName { get; set; }
+        /// <summary>
+        /// Contains an extended human-readable title that identifies this search engine.
+        /// </summary>
+        public string LongName { get; set; }
+        /// <summary>
+        /// Contains a human-readable text description of the search engine.
+        /// </summary>
+        public string Description { get; set; }
+        /// <summary>
+        /// https://github.com/dewitt/opensearch/blob/master/opensearch-1-1-draft-6.md#the-url-element
+        /// </summary>
+        public SearchLink Url { get; set; }
+        /// <summary>
+        /// Contains a set of words that are used as keywords to identify and categorize this search content.
+        /// Tags must be a single word and are delimited by the space character (' ').
+        /// </summary>
+        public string Tags { get; set; }
+        /// <summary>
+        /// Contains a URL that identifies the location of an image that can be used in association with this search content.
+        /// <example><Image height="64" width="64" type="image/png">http://example.com/websearch.png</Image></example>
+        /// </summary>
+        public string Image { get; set; }
+        public string InputEncoding { get; set; } = "UTF-8";
+        public string OutputEncoding { get; set; } = "UTF-8";
+        /// <summary>
+        /// Contains the human-readable name or identifier of the creator or maintainer of the description document.
+        /// </summary>
+        public string Developer { get; set; } = "kavitareader.com";
+
+    }
+}