fireapp-3.119.0-gh-readonly-queue-main-pr-305-91fbcb921f2126a869344141e9799dcc295a8fae.1

Chim/feature/add notification service (#305)

## Describe your changes

I've add 3 functions:

1. `send_notification` in the `NotificationService` class 
2. `get_fcm_token` and `notify_user` in the `FCMTokenRepository` class

Functionalities:

1. Given a list of fcm token, `send_notification` will allow other parts
of the program to call for sending any message or notification.
2. Given a user id, `get_fcm_token` will retrieve all fcm tokens for a
given user and return in a list of token string.
3. Gvien a userId or a list of fcm token, `send_notification` can be
used to send notification to users.


## Issue ticket number and link


[Jira](https://fireapp-emergiq-2024.atlassian.net/jira/software/projects/FIR/boards/2?selectedIssue=FIR-99)