feat(imagvideo): max_frames(n) filter

* feat: ffmpeg max_frames option in process_frames

* test: update golden files

testdata/golden/meta/alpha-webm.webm-10.meta.json

@@ -0,0 +1 @@
+{"orientation":1,"duration":12040,"width":720,"height":576,"fps":25,"selected_frame":4,"has_video":true,"has_audio":false}

testdata/golden/meta/everybody-betray-me.mkv-10.meta.json

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+{"orientation":1,"duration":7407,"width":640,"height":480,"fps":30,"selected_frame":5,"has_video":true,"has_audio":true}

testdata/golden/meta/macabre.mp4-10.meta.json

@@ -0,0 +1 @@
+{"orientation":1,"duration":3925,"width":492,"height":360,"fps":30,"selected_frame":4,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo.flv-10.meta.json

@@ -0,0 +1 @@
+{"orientation":1,"duration":2560,"width":480,"height":360,"fps":28,"selected_frame":5,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo_0.mp4-10.meta.json

@@ -0,0 +1 @@
+{"orientation":1,"duration":2544,"width":480,"height":360,"fps":30,"selected_frame":5,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo_180.mp4-10.meta.json

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+{"orientation":3,"duration":2544,"width":480,"height":360,"fps":30,"selected_frame":4,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo_270.mp4-10.meta.json

@@ -0,0 +1 @@
+{"orientation":6,"duration":2544,"width":360,"height":480,"fps":30,"selected_frame":6,"has_video":true,"has_audio":true}

testdata/golden/meta/schizo_90.mp4-10.meta.json

@@ -0,0 +1 @@
+{"orientation":8,"duration":2544,"width":360,"height":480,"fps":30,"selected_frame":7,"has_video":true,"has_audio":true}

testdata/golden/result/meta/filters%3Amax_frames%286%29/everybody-betray-me.mkv

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+{"format":"mkv","content_type":"video/x-matroska","orientation":1,"duration":7407,"width":640,"height":480,"fps":30,"selected_frame":3,"has_video":true,"has_audio":true}