Simplify dev environment: inline devcontainer, drop Docker image tooling

.devcontainer/Dockerfile

@@ -1 +1,51 @@
-FROM jslee02/dart-dev:ubuntu-jammy-v6.16
+FROM ubuntu:questing
+
+ARG DEBIAN_FRONTEND=noninteractive
+
+SHELL ["/bin/bash", "-c"]
+
+# Build tools
+RUN apt-get update -qq && apt-get install -y --no-install-recommends \
+    build-essential \
+    clang \
+    clang-format-14 \
+    cmake \
+    curl \
+    doxygen \
+    git \
+    lcov \
+    lsb-release \
+    ninja-build \
+    pkg-config \
+    software-properties-common \
+    valgrind
+
+# DART required dependencies
+RUN apt-get update -qq && apt-get install -y --no-install-recommends \
+    libassimp-dev \
+    libeigen3-dev \
+    libfcl-dev \
+    libfmt-dev
+
+# DART optional dependencies
+RUN apt-get update -qq && apt-get install -y --no-install-recommends \
+    libtinyxml2-dev \
+    liburdfdom-dev \
+    liburdfdom-headers-dev \
+    libopenscenegraph-dev \
+    liboctomap-dev \
+    libode-dev \
+    libimgui-dev \
+    libspdlog-dev
+
+# Python binding dependencies
+RUN apt-get update -qq && apt-get install -y --no-install-recommends \
+    libpython3-dev \
+    python3 \
+    python3-dev \
+    python3-numpy \
+    python3-pip \
+    python3-pytest \
+    python3-setuptools && \
+    PIP_BREAK_SYSTEM_PACKAGES=1 pip3 install --no-cache-dir --ignore-installed nanobind pytest -U && \
+    rm -rf /var/lib/apt/lists/*