added transcoding app from mitol and removed transcoding job code

[umar8hassan]

What are the relevant tickets?

fixes https://github.com/mitodl/hq/issues/6717

Description (What does it do?)

This PR aims to refactor transcoding job code to include newly created mitol.transcoding for media conversion tasks

How can this be tested?

1. Add settings for AWS_* from RC in your local .env
2. Add settings for required for gdrive to work locally.
3. Add the additional settings in .env:

# Transcoding App settings
POST_TRANSCODE_ACTIONS=videos.api.update_video_job
TRANSCODE_JOB_TEMPLATE=./videos/config/mediaconvert.json

4. Switch to this branch and rebuild containers: docker-compose up -d --build
5. Add a sample video in gdrive and sync with ocw-studio. This should trigger a transcoding job
6. To verify you execute the following command in django shell using docker-compose exec -it web ./manage shell:

from videos.models import VideoJob
from django.conf import settings
import boto3

client = boto3.client(
     "mediaconvert",
     region_name=settings.AWS_REGION,
     aws_access_key_id=settings.AWS_ACCESS_KEY_ID,
     aws_secret_access_key=settings.AWS_SECRET_ACCESS_KEY,
     endpoint_url="https://vasjpylpa.mediaconvert.us-east-1.amazonaws.com"
 )
client.get_job(Id=VideoJob.objects.order_by("-created_on").first().job_id)

• this should display the details of the latest transcode job