package/python-matplotlib: bump to version 3.4.3

- Remove upstreamed patches
- Add BR2_PACKAGE_PYTHON_CERTIFI and BR2_PACKAGE_QHULL as dependencies
- make DEPENDENCIES one per line and sort alphabetically
- Add a new file: setup.cfg. This file is needed to force matplotlib to use
  the system-provided freetype and qhull, and to disable lto.
  The setup.cfg file is copied to the source directory before configuring.

LTO must be disabled or else compile errors such as:
"Relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `_ZSt3hexRSt8ios_base'
which may bind externally can not be used when making a shared object;
recompile with -fPIC"

Signed-off-by: Adam Duskett <aduskett@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>