Add basic jobs

[hkzorman]

Whether simulated or implemented for real, the following basic jobs should be added and assigned to NPC depending on the type of building the live on or is close by.

• Farmer
• Woodcutter
• Miner
• Cooker
• Priest
• Bartender/server
• Smith

Elaborating on "simulated" jobs, means that the NPC will get random number of items that would get if actually doing the job. Example: A farmer NPC may wander the field for 4-6 Minetest hours and be assigned randomly 10-15 seeds, and 10-15 crops, as opposed to the NPC actually harvesting, getting seeds, etc.

This is the job/occupation implementation check list:

• Add spawner functionality to detect nearby building types
• NPC: Allow choosing random textures from a given texture list
• Add spawner functionality to choose number of NPC for occupations for building
• Implement occupation initialization function
• Implement schedule "check" or "query" function