[FEAT]: Endpoint for Sending SMS using Twilio API

[shedrack-alita]

##Description
Implement an API endpoint for sending SMS using Twilio API. This endpoint should allow users to send SMS messages to a specified call number.

##Acceptance Criteria

• The endpoint should be specified at post/api/v1/sms/send
• The endpoint should accept HTTP POST request.
• The endpoint should send an SMS message using Twilio API messaging content through the call number provided
• The endpoint should return a 200 status code with a success response message in JSON format

##Request Sample:

post/api/v1/sms/send
content-type: application/json

{
   "phon_number": "+2349018657226",
   "message": "Hello there! this is your first message"
}

##Response Sample:
Upon successful request, the API will return a 200 status code showing that the SMS message have been delivered.

"status": "Success",
"status_code": 200,
"message": "SMS successfully sent"

##Validation:

• If the phone number is invalid or message content is missing, then the API will return a 400 bad request status code with the error response below:

"status": "Unsuccessful",
"status_code": 400,
"message": "Message content and a valid call number must be provided"

• If an error occurs as a result of an invalid Twilio credentials, or bad network, the API wil return a 500 internal server error status code with the appropriate error message as shown:

"status": "Unsuccessful",
"status_code": 500,
"message": "SMS sending failed, please try again later"