Update List exp API to get only the experiment Names

[khansaad]

This PR fixes #1031

• Updated the existing list experiment API to have a variant to get only the experiment Names as a list of string.
• Endpoint : http://127.0.0.1:8080/listExperiments/getExperimentNames?search=<search-string>&page=1&limit=20
• By default i.e. no search-string, no page or limit, it will return all experiment names with limit set as 20 for each page.
• Sample response:

  {
  "experimentNames": [
      "quarkus-resteasy-autotune-min-http-response-time-db",
      "2quarkus-resteasy-autotune-min-http-response-time-db",
      "3quarkus-resteasy-autotune-min-http-response-time-db",
      "4quarkus-resteasy-autotune-min-http-response-time-db"
  ],
  "count": 4
  }

• Here count represents the total no. of experiment names present in the DB corresponding to the particular search-string. It will return the total experiment names count in the absence of search-string.
• Also, count will remain same for all the paginated results for each specific request

[dinogun]

Closing stale PRs