Resolve "New iteration on MX dataset summary"

Closes #254 (closed), #243 (closed)

• New group display
• proposition of alternative grouping method (one of them to be removed after feedback). Some examples to see how it differs:
  • http://localhost:3000/investigation/1336120076/datasets?sampleId=1353399367
  • http://localhost:3000/investigation/1336120076/datasets?sampleId=1353307207
  • http://localhost:3000/investigation/1336120076/datasets?sampleId=1352978057
  • http://localhost:3000/investigation/1336120076/datasets?sampleId=1353092172