Team 4 shadowdash new language design

[waynewangyuxuan]

Commits combined into one.

[yw5490]

Test Plan:
Added the following test to be automatically performed by Circle CI:

check_success() {
  if [ $? -eq 0 ]; then
    echo "$1"
  else
    echo "$1"
    exit 1
  fi
}

cd src/shadowdash

g++ -w -std=c++17 -fPIC -c manifest.cc  manifest.h
check_success ".o compiled successfully"

g++ -w -shared -o manifest.so manifest.o
check_success ".so compiled successfully"

cd ../..

Test Result:
Overall Test
Test to compile manifest.o and manifest.so

[kyotov]

make sure you are following general comments i have in https://docs.google.com/document/d/11e8zR3kcm7B-D6brAH_D4OgtYBEf94GZwQIXrnti5hM/edit?tab=t.0 and let me know to look again.
(not all points apply to you but some do)

[yw5490]

Latest PR: #26