add: multi-language setup for /tests/coverage endpoint

[fayekelmith]

Request:

 curl "http://localhost:7799/tests/coverage" | jq .

Response:

[
  {
    "language": "typescript",
    "unit_tests": {
      "total": 536,
      "total_tests": 9,
      "covered": 3,
      "percent": 0.56,
      "total_lines": 9675,
      "covered_lines": 157,
      "line_percent": 1.62
    },
    "integration_tests": {
      "total": 2,
      "total_tests": 6,
      "covered": 0,
      "percent": 0.0,
      "total_lines": 2,
      "covered_lines": 0,
      "line_percent": 0.0
    },
    "e2e_tests": null,
    "mocks": null
  },
  {
    "language": "rust",
    "unit_tests": {
      "total": 536,
      "total_tests": 9,
      "covered": 3,
      "percent": 0.56,
      "total_lines": 9675,
      "covered_lines": 157,
      "line_percent": 1.62
    },
    "integration_tests": {
      "total": 536,
      "total_tests": 6,
      "covered": 8,
      "percent": 1.49,
      "total_lines": 9675,
      "covered_lines": 210,
      "line_percent": 2.17
    },
    "e2e_tests": {
      "total": 2,
      "total_tests": 32,
      "covered": 0,
      "percent": 0.0,
      "total_lines": 2,
      "covered_lines": 0,
      "line_percent": 0.0
    },
    "mocks": null
  }
]

---

Request:

curl "http://localhost:7799/tests/coverage?language=rust" | jq . 

Response:

[
  {
    "language": "rust",
    "unit_tests": {
      "total": 536,
      "total_tests": 9,
      "covered": 3,
      "percent": 0.56,
      "total_lines": 9675,
      "covered_lines": 157,
      "line_percent": 1.62
    },
    "integration_tests": {
      "total": 536,
      "total_tests": 6,
      "covered": 8,
      "percent": 1.49,
      "total_lines": 9675,
      "covered_lines": 210,
      "line_percent": 2.17
    },
    "e2e_tests": {
      "total": 2,
      "total_tests": 32,
      "covered": 0,
      "percent": 0.0,
      "total_lines": 2,
      "covered_lines": 0,
      "line_percent": 0.0
    },
    "mocks": null
  }
]

[Evanfeenstra]

to keep it backward compatible, can we keep the old format, but add each individual language in "languages" array

so the global would combine from each language

{ 
  "unit_tests": {
      "total": 1034,
      "total_tests": 9,
      "covered": 3,
      "percent": 0.56,
      "total_lines": 9675,
      "covered_lines": 157,
      "line_percent": 1.62
    },
    "integration_tests": {
      "total": 2,
      "total_tests": 6,
      "covered": 0,
      "percent": 0.0,
      "total_lines": 2,
      "covered_lines": 0,
      "line_percent": 0.0
    },
    "e2e_tests": null,
    "mocks": null,
    "languages": [
      {
        "name": "typescript",
        "unit_tests": {
          "total": 400,
          "total_tests": 9,
          "covered": 3,
          "percent": 0.56,
          "total_lines": 9675,
          "covered_lines": 157,
          "line_percent": 1.62
        }
      }
    ]
  }