build: ndk 28, build-tools 35.0.1, openssl 3.4.1

bump build sdk to 35

for record support

build: move to build-tools 34

build: jdk 21, bump gradle and agp for compatibility

Containerfile: remove aarch64 boost, add native clang

in preparation of building boost via ceph build

Containerfile: clean pacman pkg cache

Revert "move to android-ndk-beta"

This reverts commit 1a21f55b63f7d097dbc21229d74dc01d20e1f56e.

move to android-ndk-beta

for better c++20 stdlib support, and prepare for moving to reef

gradle: wire up ceph

Containerfile: riggings for ghcr

Containerfile: initial work for containerized building

one step forward to finally hook ceph cmake onto gradle?
maybe we still want to ship prebuilts on a build variant for faster
development? idk
or, can we eventually hook every dependencies and stop using aur
contents, which make containerization not really that desired?