Add support for -strict option on FFmpegBuilder

[Euklios]

Is your feature request related to a problem? Please describe.
The option -strict can currently only be set on AbstractFFmpegStreamBuilder.
Given the current version of the library, this limits the option to only OutputBuilders.
It should also be exposed via FFmpegBuilder, allowing it to be set for the entire execution.

Describe the solution you'd like

• Add setStrict on FFmpegBuilder
• Extract the Strict enum into it's own class
• Create a test based on Add FFmpegInputBuilder to support per input options #318 Comment

Describe alternatives you've considered
The comment above shows an alternative, by creating a sub-class and adding the argument manually. This shouldn't be necessary.