Create a Ruuter service to link text input with national holidays common services

[turnerrainer]

[!NOTE] This is a sub-issue of #63 and #60

AS A Product Owner I WANT TO test if text input initiates applicable national holidays common services SO THAT I could verify its intended functionality

Acceptance Criteria

• [x] Every endpoint of #60 is triggered by 1 specific keyword

  E.g. "#prev_national_holiday" would trigger /calendar/national-holidays/previous

• [ ] All #keywords are hard-coded in Ruuter DSL /calendar/national-holidays/search
• [ ] Use Ruuter's conditional switch functionality to trigger applicable endpoints based on input
• [ ] Based on triggering keyword, a request to an appropriate endpoint is made

DSL

• [ ] Service provided via Ruuter's /calendar/national-holidays/search endpoint

Example

Request

curl localhost:8080/calendar/national-holidays/search
   -H "Content-Type: application/json"
   -d '{"keyword": "#prev_national_holiday"}'

Response

{
    "response": {
        "date": "2024-08-20",
        "name": "taasiseseisvumispäev"
    }
}

[matKlju]

https://github.com/buerokratt/Common-Services/issues/64