Fix issues with updating Conditional Formatting when inserting/deleting rows/columns

[MarkBaker]

This is:

- [X] a bugfix
- [ ] a new feature

Checklist:

• Changes are covered by unit tests
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

Fix issues with updating Conditional Formatting when inserting/deleting rows/columns

• Update existing ranges, expanding or reducing if necessary, rather than trying to clone the CF for each individual cell.

  This is also better for memory usage, with fewer CF rules and styles being maintained

• Update conditions, so that cell references and formulae are maintained correctly.

Note that absolute as well as relative cell references should be updated in conditions

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This is a the third and final step toward allowing updates to absolute cell references, required to update Conditional Formatting rules when columns/rows are inserted/deleted as highlighted by Issue #2678; the final step in a multi-step process.

Step 1
Refactor the cell reference update logic to make it easier to modify, and to test the planned modifications
This may also make the code more performant, as it allows elimination of a lot of code duplication in the different methods to update different components of the worksheet. PR #2682

Step 2
Modify the cell reference update logic to accept a flag indicating whether it should update absolute as well as relative cell references PR #2685

Step 3
Add the logic to update Conditional Formatting ranges and rules when inserting/deleting rows/columns