Replacing AWSBraketJob with AmazonBraketTask (qiskit-community#105)

* replacing AWSBraketJob with AmazonBraketTask

* run the notebooks containing AmazonBraketTask

* deprecation warning added for AWSBraketJob class

* formatting fixed

* re-add <JOB_ARN>

* fix breaking changes on /provider/__init__.py and __init__.py

* rename job_id to task_id argument for AmazonBraketTask()

* rename braket_jobs_states to braket_tasks_states

* add task_id method to access the task_id similar to the one we have in the JobV1 class

* adding tests for new class 'AmazonBraketTask' and old class 'AWSBraketJob'

* formatting test_braket_job.py

* correcting definition of AWSBraketJob

* rewriting line 184 in braket_job.py

* adding class docstring to AWSBraketJob

* standard import 'from warnings import warn'  placed before 'from braket.aws import AwsQuantumTask' (wrong-import-order)

* docstring fix in test_braket_job.py

* assert the job id in test_AWS_job() function in test_braket_job.py

* running how to notebook #0

* running how to notebook #1

* running how to notebook #2

* running how to notebook #3

* running how to notebook number 5

* running tutorial  notebook number 3

* tutorial number 0