Delete ewsghana app

[jingcheng16]

Technical Summary

Ticket: https://dimagi.atlassian.net/browse/SAAS-16525

I came across this app and noticed it is no longer used so want to remove it.

Jenny also confirmed this is for a project that is over.

ewsghana was a project that had a lot of custom code. It's over now, and most of the related code has been deleted (see PRs like this and this).

I searched the remaining 3 models in the code, no reference.

Checked number of data on production, I think this is an amount that can be handled in deploy.

In [1]: from custom.ewsghana.models import *

In [2]: FacilityInCharge.objects.count()
Out[2]: 609

In [3]: EWSExtension.objects.count()
Out[3]: 1011

In [4]: SQLNotification.objects.count()
Out[4]: 56443

Safety Assurance

Safety story

I searched the remaining 3 models in the code, no reference. Also checked all the entities that have reference to these 3 models, mainly some constraint and index.

Automated test coverage

QA Plan

Migrations

• The migrations in this code can be safely applied first independently of the code

Rollback instructions

• This PR can be reverted after deploy with no further considerations
  I didn't write any revert code, since I believe we won't do reversion. Also, even if reversion, all the data is already permanently deleted.

Labels & Review

• Risk label is set correctly
• The set of people pinged as reviewers is appropriate for the level of risk of the change

[millerdev]

Is this needed for anything other than ewsghana? If not, maybe it can be removed too?

[jingcheng16]

It is needed for custom reports. Jenny will have a PR to consolidate this file, then standard reports, custom reports, UCR will use the same code.

[jingcheng16]

Offlined with Danny and did some check together, Danny signed off on deleting it, so I'll merge the PR.