Use a filters as config option instead of hard coding them

[allo-]

Allow to configure filters like

background_filters: ["grayscale", ("blur", 5)]
mask_filters: [("blur", 5)]
foreground_filters: []

replacing config options like blur_background.

[allo-]

Proposed Syntax:

• filters: [("x", 10, 20)] runs filters.x(*filter[1:]) (flat positional arguments)
• filters: [("x", [10, 20])] runs filters.x(*filter[1]) (list positional arguments)
• filters: [("x", {width: 10, height: 20})] runs filters.x(**filter[1]) (kwargs)
• filters: [("x", 1), ("y", [2, 3])] runs filters.y(filters.x(frame, *filters[0][1:]), *filters[1][1]) (multiple filters with arguments)