PLT-4277: Allow larger custom emojis by resizing (#4447)

Add function to resize image using resize.Thumbnail. Add function to
resize gif using previous function. Add function to convert image.Image
to image.Palleted. Add logic to identify image type and resize them if
they are larger than MaxEmojiHeight or MaxEmojiWidth. Also increase
MaxEmojiFileSize.

* fix: Add github.com/nfnt to vendor

* fix: Fix max file size and if logic in resizeEmoji

* test: Fix and add new tests for new resize feature

* fix: Fix and update translations to fit new feature

* fix: Add requested changes

i18n/en.json

@@ -791,7 +791,7 @@
   },
   {
     "id": "api.emoji.create.too_large.app_error",
-    "translation": "Unable to create emoji. Image must be less than 64 KB in size."
+    "translation": "Unable to create emoji. Image must be less than 1 MB in size."
   },
   {
     "id": "api.emoji.delete.permissions.app_error",
@@ -822,8 +822,20 @@
     "translation": "Unable to create emoji. File must be a PNG, JPEG, or GIF."
   },
   {
-    "id": "api.emoji.upload.large_image.app_error",
-    "translation": "Unable to create emoji. Image must be at most 128 by 128 pixels."
+    "id": "api.emoji.upload.large_image.decode_error",
+    "translation": "Unable to create emoji. An error occurred when trying to decode the image."
+  },
+  {
+    "id": "api.emoji.upload.large_image.encode_error",
+    "translation": "Unable to create emoji. An error occurred when trying to encode the image."
+  },
+  {
+    "id": "api.emoji.upload.large_image.gif_decode_error",
+    "translation": "Unable to create emoji. An error occurred when trying to decode the GIF image."
+  },
+  {
+    "id": "api.emoji.upload.large_image.gif_encode_error",
+    "translation": "Unable to create emoji. An error occurred when trying to encode the GIF image."
   },
   {
     "id": "api.file.get_file.public_disabled.app_error",