`tns preview` does not handle custom binary files

Is your feature request related to a problem? Please describe.

The tns preview command syncs files based on their file extension. If the file is binary it should be sent as base64 encoded file. Currently the check is based on a third party dependency istextorbinary
https://github.com/NativeScript/nativescript-cli/blob/8722364da49c9950e65d79014e66d3a17a59d0ce/lib/services/livesync/playground/preview-app-files-service.ts#L65

This lib only supports a limited set of binary extensions
https://github.com/bevry/binaryextensions/blob/master/source/index.json

Describe the solution you'd like

Add a parameter to the command to allow adding additional extensions that must be handled as binary.

从 lib/services/livesync/playground/preview-app-files-service.ts 第 65 行附近的文件类型检查开始，然后跟踪 tns preview 命令参数的定义方式。添加一种指定必须作为二进制文件处理的额外扩展名的方法，并验证这些文件是否以 base64 编码的内容进行同步。