devcontainer: simplify and remove Dockerfile

Signed-off-by: Sven Anderson <sven@redhat.com>

.devcontainer/Dockerfile

@@ -1,13 +0,0 @@
-ARG CEPH_VERSION
-FROM go-ceph-ci:${CEPH_VERSION}
-
-RUN cd /tmp && \
-  go get -v \
-    golang.org/x/tools/gopls \
-    honnef.co/go/tools/... \
-    golang.org/x/lint/golint \
-    github.com/mgechev/revive \
-    github.com/uudashr/gopkgs/v2/cmd/gopkgs \
-    github.com/ramya-rao-a/go-outline \
-    github.com/go-delve/delve/cmd/dlv \
-    github.com/golangci/golangci-lint/cmd/golangci-lint

.devcontainer/devcontainer.json

@@ -2,18 +2,18 @@
 // https://github.com/microsoft/vscode-dev-containers/tree/v0.166.1/containers/docker-existing-dockerfile
 {
     "name": "go-ceph",
-    "initializeCommand": "make CEPH_VERSION=octopus ci-image",
     "build": {
         // Sets the run context to one level up instead of the .devcontainer folder.
-        //"context": "..",
-        "dockerfile": "Dockerfile",
+        "context": "..",
+        "dockerfile": "../testing/containers/ceph/Dockerfile",
         "args": {
             "CEPH_VERSION": "octopus"
         }
     },
+    "workspaceMount": "source=${localWorkspaceFolder},target=/go/src/github.com/ceph/go-ceph,type=bind,consistency=cached",
+    "workspaceFolder": "/go/src/github.com/ceph/go-ceph",
     // Set *default* container specific settings.json values on container create.
     "settings": {
-        "terminal.integrated.shell.linux": "/bin/bash",
         "go.toolsManagement.checkForUpdates": "local",
         "go.toolsManagement.autoUpdate": true,
         "go.useLanguageServer": true,
@@ -45,6 +45,7 @@
     ],
     // Uncomment to use the Docker CLI from inside the container. See https://aka.ms/vscode-remote/samples/docker-from-docker.
     // "mounts": [ "source=/var/run/docker.sock,target=/var/run/docker.sock,type=bind" ],
+    "mounts": [ "source=test_ceph_go_cache,target=/go,type=volume" ],
     // Uncomment to connect as a non-root user if you've added one. See https://aka.ms/vscode-remote/containers/non-root.
     // "remoteUser": "vscode"
 }