Refactor the config system once again this time for good

[ChillerDragon]

the server.cnf is basically a dotfile and thus native bash ... duh

do not reimplement that in bash. Just source it. Then the config vars in the code also match the config vars in the file that would be cool too for fast lookup. And it allows for things like:

unix_user=teeworlds
git_root=/home/$unix_user/git

^ which would help a lot with maintenance!

It should still keep the value checks tho. No invalid cfg assignments and no invalid values.

[ChillerDragon]

custom build flags and environments are currently broken.

gotta do the array magic here

server/lib/include/update/cmake.sh

Lines 73 to 75 in d1eccb7

	local pointer_cmake_flags="$5" # has to be name of an array variable
	local pointer_cmake_flags_arr="$5[@]"
	local arg_cmake_flags=("${!pointer_cmake_flags_arr}") # parameter expansion

and also somehow custom environemnts like those break the build:

# env_build=CC=clang CXX=clang++ CXXFLAGS="-fsanitize=address,undefined -fsanitize-recover=address,undefined -fno-omit-frame-pointer" CFLAGS="-fsanitize=address,undefined -fsanitize-recover=address,undefined -fno-omit-frame-pointer"
# env_runtime=UBSAN_OPTIONS=log_path=./logs/SAN:print_stacktrace=1:halt_on_errors=0 ASAN_OPTIONS=log_path=./logs/SAN:print_stacktrace=1:check_initialization_order=1:detect_leaks=1:halt_on_errors=0
env_build=CXXFLAGS=-pg CFLAGS=-pg LDFLAGS=-rdynamic

[ChillerDragon]

I would also love to see array options

conf_var=(value1 value2 value3)