Queue coverart (#127)

* Added new module

* Added new endpoint

* Formatting

* Migration changes

* Fix routing issue

* Fixed migration

* Added functionality and test

* Test change

* Cleanup

* Code formatting

src/callers/mod.rs

@@ -1,3 +1,4 @@
+pub mod coverart;
 pub mod metadata;
 pub mod song;
 
@@ -6,4 +7,5 @@ pub mod endpoints {
     pub const QUEUESONGDATA: &str = "/api/v2/song/queue/{id}";
     pub const NEXTQUEUESONG: &str = "/api/v2/song/queue/next";
     pub const QUEUEMETADATA: &str = "/api/v2/song/metadata/queue";
+    pub const QUEUECOVERART: &str = "/api/v2/coverart/queue";
 }