Allow configuring cache folder (#2357)

* Set all clients to dev_download for make get-music

* Use multiple TranscodingCache instances in tests

This fixes flaky tests. The issue is that the TranscodingCache object
was being reused in tests from media_stream_Internal_test.go and
media_stream_test.go. If tests from the former was run first, the cache
would be filled up, so that when running tests from the latter, the `NON
seekable` test would fail.

* Allow configuring cache folder

This commit introduces a new configuration option to configure the cache
folder. This allows the cache to be in a separate folder such as
/var/cache/navidrome on Linux distributions.

* Fix tests

* Removed unused test setup code

---------

Co-authored-by: Deluan <deluan@deluan.com>
Co-authored-by: Deluan <deluan@navidrome.org>

utils/cache/file_caches.go

@@ -209,7 +209,7 @@ func newFSCache(name, cacheSize, cacheFolder string, maxItems int) (fscache.Cach
 
 	lru := NewFileHaunter(name, maxItems, int64(size), consts.DefaultCacheCleanUpInterval)
 	h := fscache.NewLRUHaunterStrategy(lru)
-	cacheFolder = filepath.Join(conf.Server.DataFolder, cacheFolder)
+	cacheFolder = filepath.Join(conf.Server.CacheFolder, cacheFolder)
 
 	var fs *spreadFS
 	log.Info(fmt.Sprintf("Creating %s cache", name), "path", cacheFolder, "maxSize", humanize.Bytes(size))