* fix: separate vertical alignment enums for table and section properties
- Introduced `VerticalAlignTable` for table-cell vertical alignment with valid values: `top`, `center`, and `bottom`.
- Added `VerticalAlignSection` for section properties, extending `VerticalAlignTable` with an additional value `both`.
- Marked the original `VerticalAlign` as deprecated for backward compatibility, directing users to the new enums.
- Updated type definitions for better clarity on valid vertical alignments.
* refactor: update vertical alignment imports and types for section and table properties
- Renamed `VerticalAlign` to `VerticalAlignSection` in section properties and `VerticalAlignTable` in table-cell properties for clarity.
- Updated type definitions to reflect the new enum names, ensuring better organization and understanding of vertical alignment options.
- Adjusted related test cases to utilize the new imports and types.
* refactor: update demos to use new enums for table and section properties for vertical alignment
Rework the way attributes are stored in ImportedXmlComponent to match elsewhere (required allowing for a null xmlKeys in the XmlAttributeComponent interface).
Rework the way paragraphs get added to the end of table cells if needed.
The goal in both reworks is to not mess around with the objects output from `prepForXml` if we can avoid it.
Made the output of RunProperties, ParagraphProperties, TableCellProperties, TableRowProperties, and TableProperties all optional based on whether they contain any attributes or children. Changed code in PageBorders, TableCellMargin, and TableCellBorders that implemented this same thing by overriding `prepForXml` so that it uses the new XmlComponent subclass instead.
Removed commented out code that attempted to fix-up XML output and make proper empty elements.
Fixed all affected tests.
Turn off `no-null-keyword` in the linter as we need to use null to signal to the `xml` library to create an empty element with no attributes (`undefined` will not work in its place).
Fixes#306
The page number type DECIMAL is already the default in Word, there is no need to force this to be the default option in the default section, like it was.
