Add ubuntu:22.04 docker images (#1618)

Ubuntu 22.04 base image and examples using github, a copy instruction and volumes.

I was using this to run examples on a windows machine since it is more comfortable than switching OS or using the WSL subsystem directly.
If this is something that other people would like to have  I can add other versions of ubuntu and other linux distributions.

.devcontainer/Dockerfile

@@ -1,41 +0,0 @@
-# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-# Exceptions. See /LICENSE for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-FROM ubuntu:22.04
-
-# Install apt tools:
-#   git: Used by VS Code.
-#   golang: Used for Bazelisk and Buildifier.
-#   python3: For Carbon tools.
-#   gnupg, software-properties-common, wget: For llvm.sh.
-# apt-get update and install together per Docker best practice.
-RUN apt-get update && \
-  apt-get install -y \
-  git \
-  gnupg \
-  golang \
-  python3-pip \
-  python3.9 \
-  software-properties-common \
-  wget
-
-ENV PATH="/root/go/bin:${PATH}"
-# Bazelisk is used for Carbon builds.
-RUN go install github.com/bazelbuild/bazelisk@v1.14.0
-RUN ln -s /root/go/bin/bazelisk /root/go/bin/bazel
-# Buildifier is used by the Bazel VS Code extension.
-RUN go install github.com/bazelbuild/buildtools/buildifier@5.1.0
-
-# Install LLVM from apt.llvm.org.
-RUN wget https://apt.llvm.org/llvm.sh
-RUN chmod +x llvm.sh
-RUN ./llvm.sh 15 all
-RUN rm llvm.sh
-# Add the lib dir to the PATH. This helps Bazel find clang and VS Code find
-# clangd, without version suffixes.
-ENV PATH="/usr/lib/llvm-15/bin:${PATH}"
-
-# Update pip and install black and pre-commit.
-RUN pip3 install -U pip
-RUN pip3 install black pre-commit

.devcontainer/devcontainer.json

@@ -1,7 +1,7 @@
 {
   "name": "carbon-lang",
   "build": {
-    "dockerfile": "Dockerfile",
+    "dockerfile": "../docker/ubuntu2204/base/Dockerfile",
     "args": {
       "TAG": "3.5.6"
     }