ademant/minetest_xpfw: Add Framework for Managing different Kind of experience, e.g. farming experience for getting faster crops as more farming you have done.

A. Demant 1839396c82 some textures; errors		6 lat temu
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src	1839396c82 some textures; errors	6 lat temu
xpfw_death.png	1839396c82 some textures; errors	6 lat temu
xpfw_farming.png	1839396c82 some textures; errors	6 lat temu
xpfw_hiking.png	1839396c82 some textures; errors	6 lat temu
xpfw_miner.png	1839396c82 some textures; errors	6 lat temu