Make aarch64 keyrings and x86_64 keyrings definitions be separate instead of addon

See merge request !22

fix typo

See merge request !21

- readout the default values from makepkg.conf

This reverts commit 61afe523.

- use default settings from makepkg.conf
- edit as needed

address !20 and !16 and f59ee159

This reverts commit f59ee159.

- use C.UTF-8 by default
- clean out pacman-mirrors

- Enable link time optimization (LTO) of packages by default by adding the
-flto flag. This provides smaller, faster executables/DSOs, and improves
GCC diagnostics.
- see also: https://gitlab.archlinux.org/archlinux/devtools/-/commit/16b7a0e7e8ef795621172cb08887a2f86f0b0222
- Arch didn't enable it in pacman package, hence add it here

[util-chroot] use C.UTF-8 by default

See merge request !19

- to have a cleaner chroot remove pacman-mirrors and its pyhton dependencies

Reworked the pkg_build function and added get_src_dir function: now checking PKGBUILD if present pkgver() function and update it; now SRCDIR is ignored, in any case the sources are download inside the PKGBUILD folder during the building but cleaned after.

Signed-off-by: Stefano Capitani <stefano@manjaro.org>

This reverts commit dcb33758.

This reverts commit 3d992126.

This reverts commit e19b6b8f.