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>

core/media_streamer_Internal_test.go

@@ -2,10 +2,8 @@ package core
 
 import (
 	"context"
-	"os"
 
 	"github.com/navidrome/navidrome/conf"
-	"github.com/navidrome/navidrome/conf/configtest"
 	"github.com/navidrome/navidrome/log"
 	"github.com/navidrome/navidrome/model"
 	"github.com/navidrome/navidrome/model/request"
@@ -16,21 +14,10 @@ import (
 
 var _ = Describe("MediaStreamer", func() {
 	var ds model.DataStore
-	ctx := log.NewContext(context.TODO())
+	ctx := log.NewContext(context.Background())
 
 	BeforeEach(func() {
-		DeferCleanup(configtest.SetupConfig())
-		conf.Server.DataFolder, _ = os.MkdirTemp("", "file_caches")
-		conf.Server.TranscodingCacheSize = "100MB"
 		ds = &tests.MockDataStore{MockedTranscoding: &tests.MockTranscodingRepo{}}
-		ds.MediaFile(ctx).(*tests.MockMediaFileRepo).SetData(model.MediaFiles{
-			{ID: "123", Path: "tests/fixtures/test.mp3", Suffix: "mp3", BitRate: 128, Duration: 257.0},
-		})
-		testCache := GetTranscodingCache()
-		Eventually(func() bool { return testCache.Available(context.TODO()) }).Should(BeTrue())
-	})
-	AfterEach(func() {
-		_ = os.RemoveAll(conf.Server.DataFolder)
 	})
 
 	Context("selectTranscodingOptions", func() {