adapting for hawkey behaviour of latest filter option in Query
removed by_name function from queries.py
removed by_repo function from queries.py
removed installed_exact function from queries.py
removed by_file function from queries.py
removed latest_installed_per_arch function from queries.py
removed latest_available_per_arch function from queries.py
removed downgrades_by_name function from queries.py
removed updates_by_name function from queries.py
INSTALLONLYPKGS: fix a typo

Without coma, Python merges the two lines.
remove: config.group_package_types.

Document this change.
remove: config.upgrade_requirements_on_install.

not used by the solver anyway.
rename: Base.activate_sack() -> Base.fill_sack().

More intuitive, sounds less technical.
rename: Base.build_transaction() -> Base.resolve()

More intuitive.
refactor: Comps.*iter methods are not properties.

Methods with iterators for return values are poor candidates for properties,
iterators are by nature quite mutable.
doc: delete the obsoleted API docs
Officially call dnf.yum.config.YumConfig just dnf.conf.Conf.
doc: disable html_static_path.

One less build-time warning.
doc: foundations of the API documentation.
INSTALLONLYPKGS cleanup, add installonlypkg(kernel)

Remove all unneeded and obsoleted installonly provides.
Add a new provide installonlypkg(kernel) intended to replace
kernel & kernel-source & kernel-devel in the future.