Add video support

[mat-hek]

This involves:

• checking how the system behaves when sending and processing much bigger data chunks
• adding abstraction over NIFs (https://github.com/membraneframework/membrane-native/issues/1)
• adding native payload type Support for different payload types #68

[mspanc]

@mat-hek @jarekdragan the last checkbox (adding mechanism for streams synchronization) is huge, it should not be marked as v0.2.

[mat-hek]

@mspanc ok, removed it from here

[mrkaspa]

What is the status on this I would like to test this feature

[mat-hek]

@mrkaspa In fact, this is already done. Some elements that may be useful:

• https://github.com/membraneframework/membrane-element-ffmpeg-h264
• https://github.com/membraneframework/membrane-element-sdl
• https://github.com/membraneframework/membrane-element-rtp-h264