Add support for C/C++

Description

We should have support for C/C++ out of the box in Eclipse Che.

The work would consist in integrating existing C/C++ language server and provide default stack for it.

• Ensure VS Code extensions [1] works with local Theia
  • https://github.com/theia-ide/theia/pull/5795
  • https://github.com/theia-ide/theia/pull/5803
• Compare [3] [4] with VS Code extension [1] https://github.com/eclipse/che/issues/13698#issuecomment-515403416
• Build and host vsix package for [3] [4] https://github.com/che-incubator/che-cpptools
• dockerfile
  • https://github.com/eclipse/che-theia/pull/401
• Devfile
  • https://github.com/eclipse/che/issues/14131
  • https://github.com/eclipse/che-devfile-registry/pull/73
  • https://github.com/eclipse/che/issues/14290
  • https://github.com/eclipse/che/issues/14289
• Che plugin
  • https://github.com/eclipse/che-plugin-registry/pull/197
• Exclude @theia/cpp extension
  • https://github.com/eclipse/che-theia/pull/396
• Update Language support troubleshooting document [2]
• Update getting-started factories
• Go to definition feature doesn’t work
  • Theia can’t open files located in a sidecar container https://github.com/eclipse/che/issues/13614

Reference: [1] https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools [2] https://docs.google.com/document/d/182PBN5LBNTlbhsqqsb5QHg9t5HNK3rSLrnIMPSGjyN0/edit#heading=h.tyhhnnuon2rs [3] https://github.com/eclipse-cdt/cdt-vscode [4] https://github.com/eclipse-cdt/cdt-gdb-vscode

[slemeur]

from @ferdaarikan: We should also reach out to: https://github.com/eclipse-cdt/cdt-vscode and check if they would be interested to publish the CDT VS Code extension to Che.

[tolusha]

Here is the devfile for the testing purpose to play with c/c++ tools

---
apiVersion: 1.0.0
metadata:
  name: cpp
projects:
  -
    name: cpp-hello-world
    source:
      type: git
      location: 'https://github.com/che-samples/cpp-hello-world'
components:
-
  type: chePlugin
  reference: https://raw.githubusercontent.com/tolusha/plugins-registry/master/plugins/tolusha/cpptools/0.1/meta.yaml
  alias: cpp-plugin
  preferences:
    clangd.path: /usr/bin/clangd
    cdt.clangd.binaries.enable: false
-
  type: dockerimage
  alias: cpp-dev
  image: registry.centos.org/centos/devtoolset-7-toolchain-centos7
  command: ['sleep']
  args: ['infinity']
  memoryLimit: 512Mi
  mountSources: true
commands:
  -
    name: build
    actions:
      - type: exec
        component: cpp-dev
        command: g++ -g hello.cpp -o hello.out
        workdir: ${CHE_PROJECTS_ROOT}/cpp-hello-world
  -
    name: debug
    actions:
      - type: vscode-launch
        referenceContent: >
          {
            "version": "0.2.0",
            "configurations": [
                {
                    "type": "gdb",
                    "name": "Debug c++ application",
                    "request": "launch",
                    "program": "/projects/cpp-hello-world/hello.out"
                }
            ]
          }