Add states for Organisations

The elections that would have required this modification have been called off. **Please do not attempt to solve this Issue.**

We're keeping it open in order to server as a reminder of the changes we have planned for.

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Due to the fact that the same platform will be used across multiple election rounds, the states in which an organisation / elector can exist should be updated:
- Pending approval
- Eligible to vote
- Ineligible to vote
- Disabled
- Rejected

The mechanisms through which an org. transitions between these states is a work in progress with @overeha