* fix logging_level: make logging level specified in qlib.init apply to all loggers
* downgrade loglevel in expmanager __init__ to debug (it will be called in each process in multiprocessing operations such as read data)
* correct gramma error
* fix black lint
* use functor to cache loggers and set level
* correct black lint
* correct pylint
* correct pylint
This commit improves the documentation (rst files) only in the
following three ways:
* Aligned section headers with their underline/overline punctuation characters
* Deleted all trailling whitespaces in rst files
* Deleted a few trailling newlines at the end of the rst files
Co-authored-by: Bingyao Liu <Bingyao.Liu@sofund.com>
