[API] Implement metrics ingestion endpoint

[hayk96]

Is your feature request related to a problem? Please describe.
Create a new endpoint for metrics ingestion. The idea is to allow users to easily write their custom data into Prometheus, for example, by making a POST request with a defined JSON body that will be converted into Prometheus metrics on the fly.

Describe the solution you'd like
Required a new API for metrics ingestion. Once the server receives JSON data it should implement a Remote Write request.

Describe alternatives you've considered
N/A

Additional context

input data JSON example:

{
  "__name__": "my_custom_metric",
  "label_1": "MyCustomLabel-1",
  "label_2": "MyCustomLabel-2",
  "label_N": "MyCustomLabel-N",
  "__value__": 100
}

output time-series example

my_custom_metric{"label_1": "MyCustomLabel-1", "label_2": "MyCustomLabel-2", "label_N": "MyCustomLabel-N"} 100 @ 1734732148.316