Improved dev environment (#2211)

* Improved dev env setup

* Cleanup duplicate checks

* Applied PR feedback

* Updated go.mod/go.sum

* go mod tidy

* Update .devcontainer/devcontainer.json

* Update pkg/http/server_test.go

Co-authored-by: Jan Larwig <jan@larwig.com>

* Create launch.json

* Update .devcontainer/Dockerfile

* Apply suggestions from code review

---------

Co-authored-by: Jan Larwig <jan@larwig.com>

.devcontainer/Dockerfile

@@ -0,0 +1,14 @@
+FROM mcr.microsoft.com/vscode/devcontainers/go:0-1.19
+
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+    pre-commit \
+    vim \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* \
+    && mkdir -p /go/pkg \
+    && chmod -R a+w /go/pkg
+
+WORKDIR /workspace