[performance] media processing improvements (#1288)

* media processor consolidation and reformatting, reduce amount of required syscalls

Signed-off-by: kim <grufwub@gmail.com>

* update go-store library, stream jpeg/png encoding + use buffer pools, improved media processing AlreadyExists error handling

Signed-off-by: kim <grufwub@gmail.com>

* fix duration not being set, fix mp4 test expecting error

Signed-off-by: kim <grufwub@gmail.com>

* fix test expecting media files with different extension

Signed-off-by: kim <grufwub@gmail.com>

* remove unused code

Signed-off-by: kim <grufwub@gmail.com>

* fix expected storage paths in tests, update expected test thumbnails

Signed-off-by: kim <grufwub@gmail.com>

* remove dead code

Signed-off-by: kim <grufwub@gmail.com>

* fix cached presigned s3 url fetching

Signed-off-by: kim <grufwub@gmail.com>

* fix tests

Signed-off-by: kim <grufwub@gmail.com>

* fix test models

Signed-off-by: kim <grufwub@gmail.com>

* update media processing to use sync.Once{} for concurrency protection

Signed-off-by: kim <grufwub@gmail.com>

* shutup linter

Signed-off-by: kim <grufwub@gmail.com>

* fix passing in KVStore GetStream() as stream to PutStream()

Signed-off-by: kim <grufwub@gmail.com>

* fix unlocks of storage keys

Signed-off-by: kim <grufwub@gmail.com>

* whoops, return the error...

Signed-off-by: kim <grufwub@gmail.com>

* pour one out for tobi's code <3

Signed-off-by: kim <grufwub@gmail.com>

* add back the byte slurping code

Signed-off-by: kim <grufwub@gmail.com>

* check for both ErrUnexpectedEOF and EOF

Signed-off-by: kim <grufwub@gmail.com>

* add back links to file format header information

Signed-off-by: kim <grufwub@gmail.com>

Signed-off-by: kim <grufwub@gmail.com>

internal/typeutils/internaltofrontend.go

@@ -663,7 +663,7 @@ func (c *converter) InstanceToAPIInstance(ctx context.Context, i *gtsmodel.Insta
 				CharactersReservedPerURL: instanceStatusesCharactersReservedPerURL,
 			},
 			MediaAttachments: &apimodel.InstanceConfigurationMediaAttachments{
-				SupportedMimeTypes:  media.AllSupportedMIMETypes(),
+				SupportedMimeTypes:  media.SupportedMIMETypes,
 				ImageSizeLimit:      int(config.GetMediaImageMaxSize()),       // bytes
 				ImageMatrixLimit:    instanceMediaAttachmentsImageMatrixLimit, // height*width
 				VideoSizeLimit:      int(config.GetMediaVideoMaxSize()),       // bytes