feat: Add initial support for Cancelled Date field

[claremacrae]

Description

This adds initial support for Cancelled Date field.

The following are supported and documented:

• Reading and writing Cancelled date, in Tasks Emoji and Dataview formats
• Auto-adding and removing the cancelled date
  • Automatically adding the Cancelled Date when changing the status to Cancelled
  • Automatically removing the Cancelled Date when changing the status from Cancelled
• Disabling auto-adding of Cancelled Date in Settings
• Rendering of the Cancelled date in Tasks search results - and styling based on cancelled date values

Sample tasks, in both formats:

- [-] #task Has a cancelled date ❌ 2023-04-18
- [-] #task Has a cancelled date  [cancelled:: 2023-04-18]

Not yet supported:

• Seeing the Cancelled Date in Edit Task Modal
• show/hide cancelled
• filtering, sorting and grouping by cancelled
• using the cancelled date in custom filters and groups

Motivation and Context

First stage of implementing #1855.

How has this been tested?

• New tests
• Manual exploratory testing

Screenshots (if appropriate)

Types of changes

Changes visible to users:

• New feature (prefix: feat - non-breaking change which adds functionality)
• Documentation (prefix: docs - improvements to any documentation content for users)
• Sample vault (prefix: vault - improvements to the Tasks-Demo sample vault)

Internal changes:

• Tests (prefix: test - additions and improvements to unit tests and the smoke tests)

Checklist

• My code follows the code style of this project and passes yarn run lint.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My change has adequate Unit Test coverage.

Terms

• My contribution follow this project's contributing guide
• I agree to follow this project's Code of Conduct

[claremacrae]

I've asked for feedback on this in #1855.