[feature] support processing of (many) more media types (#3090)

* initial work replacing our media decoding / encoding pipeline with ffprobe + ffmpeg

* specify the video codec to use when generating static image from emoji

* update go-storage library (fixes incompatibility after updating go-iotools)

* maintain image aspect ratio when generating a thumbnail for it

* update readme to show go-ffmpreg

* fix a bunch of media tests, move filesize checking to callers of media manager for more flexibility

* remove extra debug from error message

* fix up incorrect function signatures

* update PutFile to just use regular file copy, as changes are file is on separate partition

* fix remaining tests, remove some unneeded tests now we're working with ffmpeg/ffprobe

* update more tests, add more code comments

* add utilities to generate processed emoji / media outputs

* fix remaining tests

* add test for opus media file, add license header to utility cmds

* limit the number of concurrently available ffmpeg / ffprobe instances

* reduce number of instances

* further reduce number of instances

* fix envparsing test with configuration variables

* update docs and configuration with new media-{local,remote}-max-size variables

vendor/github.com/tetratelabs/wazero/internal/wasip1/poll.go

@@ -0,0 +1,15 @@
+package wasip1
+
+// https://github.com/WebAssembly/WASI/blob/snapshot-01/phases/snapshot/docs.md#-eventtype-enumu8
+const (
+	// EventTypeClock is the timeout event named "name".
+	EventTypeClock = iota
+	// EventTypeFdRead is the data available event named "fd_read".
+	EventTypeFdRead
+	// EventTypeFdWrite is the capacity available event named "fd_write".
+	EventTypeFdWrite
+)
+
+const (
+	PollOneoffName = "poll_oneoff"
+)