Hyperlink Support for Ods

[oleibman]

Fix #3660. Code existed to read a hyperlink in a cell for Ods, but did not exist for writing. Hyperlinks pointing within a document use a different representation than for Excel (and therefore for PhpSpreadsheet); read and write will both handle the mapping from one to the other.

While researching how to write the text part of a started Xml element, it transpired that writing 2 Ods properties (Company and Category) did not escape their values properly. Confirmed and fixed problem. I do not believe that there is such an exposure for any other writer. As it turns out, Ods Reader was not processing Company or Category properly; that is fixed.

This is:

• a bugfix
• a new feature
• refactoring
• additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• 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 and a link to the pull request if applicable
• Documentation is updated as necessary

Why this change is needed?

Provide an explanation of why this change is needed, with links to any Issues (if appropriate).
If this is a bugfix or a new feature, and there are no existing Issues, then please also create an issue that will make it easier to track progress with this PR.