Add video recording for web

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

Currently, video recording only works for Android and iOS. We can use RecordRTC to enable video recording for web.

Sample code: https://github.com/xulihang/capacitor-plugin-camera/blob/846c781c0afb5124e6f31827747bed73c46bf9e8/src/web.ts#L378-L380

**Describe the solution you'd like**

Make the `startRecordVideo` function work for web.

**Describe alternatives you've considered**

A clear and concise description of any alternative solutions or features you've considered.

**Additional context**

Add any other context or screenshots about the feature request here.