Improve settings definition in a namespace like fashion

[fmigneault]

Instead of having weaver.ini settings names like weaver.fancy_item_parameter, which makes it hard to read and quite long, we could improve it to be as follows:

[app:main]
weaver.fancy_item_parameter = true     # old
weaver.fancy_item_other = true         # old

[weaver]
fancy_item.paramter   # new
fancy_item.other      # new

This would achieve 2 goals :
1- separate the 'weaver' (or any other thing like mongo, caching, etc.) specific configurations into their relevant section.
2- leave the specific app:main and server specifications only to running the app (ie: pyramid config and eggs) to not pollute it with everything else.

Will require to load the settings using:

from configparser import ConfigParser
conf = ConfigParser()
conf.read([<ini>])
conf.get("<section>", "<name>")

For compatibility, we should plug the loaded config from ConfigParser into registry.config like follows (especially L21, don't need the other part as registry is accessible through request object):

weaver/weaver/database/__init__.py

Lines 18 to 28 in 309a694

	def includeme(config):
	LOGGER.info("Adding database...")
	from weaver.database.mongodb import MongoDatabase
	config.registry.db = MongoDatabase(config.registry)
	def _add_db(request):
	db = request.registry.db
	# if db_url.username and db_url.password:
	# db.authenticate(db_url.username, db_url.password)
	return db
	config.add_request_method(_add_db, "db", reify=True)

And the get_setting function should be improved to return a Settings(dict) object that knows how to return the appropriate setting (ie: weaver.setting would try all variants below), making it fairly transparent for the whole source code. The Settings class will have to hold references to the settings dictionary returned by registry.get_settings() (ie: pyramid-config [app:main] values) and the other settings from various INI sections.

[weaver]
setting = 

[app:main]
weaver.setting = 

To simplify the retrieval of settings, ConfigBox of https://pypi.org/project/python-box/ could be used.