New libchatfuncs

[dsblank]

This WIP PR is designed to add a library of well-designed functions for chatbots, and perhaps other uses.

It is based on initial code by @MelleKoning

Goals:

1. Use cached values when available
2. Use raw data dicts to save time
3. Don't overwhelm the caller with too much information
4. Be consistent in all functions
5. WIP: Don't use SimpleAccess or other expensive functions

Example use:

>>> from gramps.gen.db.utils import open_database
>>> db = open_database("Gramps Example", force_unlock=True)
>>> chat_db = ChatFunctions(db)
>>> tool_dict = chat_db.tools
>>> chat_db.find_people_by_name("Elizabeth")
{'handles': ['0MNKQC4STYXCRR1OV9',
  '0MVKQC8TKZIUOU43D1',
  '0N5KQCOL9V736M3WN4',
  '0PWJQCZYFXOS0HGREE',
  '14LKQCYZJEAXTS3XX',
  '1U6KQCBEC0LQKJRB7L',
  '274KQCCGGPRCM07JFX',
  '3K4KQCVYX5YU850Q3Z',
  '3PCKQC79CKJ9CVILU3',
  '3XXKQCNYIPE8OBN1J7',
  '47IKQCKIPBSO0NVZX8',
  '4M7KQCV9KPB6ULMFC',
  '6SOKQCKO2ZIW88CAZ',
  '7HZJQCK2XOH4RPJZSM',
  '7RPKQC1Y4KDHK2VUMU',
  '8PIKQCK6LASSBFJFWH',
  '9AWKQCBNBUNW4UVG7Z',
  'A99KQCNCKNWLGM2W6K',
  'AVWKQCFEVZ1VAPVY8O',
  'AZVKQCKR0GCKRZ0GAL',
  'BBUKQC5GPRPDJHJAWU',
  'BHVJQCYNVES2ZING51',
  'BOVJQCDMWND9J66TFT',
  'CV1KQC38YN9X7A1N9Y',
  'DRVKQCWBHRA73FRCOK'],
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