Deprecate `expandShorthands`/`createShorthands`/`create*Shorthand`/`expand*Shorthand`

[oliverklee]

#510 (comment)

Expanding and creating the shorthand notation is out of scope for this library. So we should remove the functionality, make all the corresponding methods a no-op and mark them these methods as @deprecated #511 will be removed in version 10.

[JakeQZ]

We could provide a link in the readme to a tag for the last release which includes the functionality, to help anyone who wants to include it in their own project, and/or encourage someone to build it into a separate package.

[ziegenberg]

One deprecation at a time:

• [TASK] Deprecate DeclarationBlock::expandShorthands #558
• [TASK] Deprecate Document::createShorthands #567
• [TASK] Deprecate Document::expandShorthands #566
• [TASK] Deprecate DeclarationBlock::expandShorthands #568
• [TASK] Deprecate DeclarationBlock::createShorthands #569
• [TASK] Deprecate DeclarationBlock::expandBorderShorthand #570
• [TASK] Deprecate DeclarationBlock::expandDimensionsShorthand #571
• [TASK] Deprecate DeclarationBlock::expandFontShorthand #572
• [TASK] Deprecate DeclarationBlock::expandBackgroundShorthand #573
• [TASK] Deprecate DeclarationBlock::expandListStyleShorthand #574
• [TASK] Deprecate DeclarationBlock::createShorthandProperties #575
• [TASK] Deprecate DeclarationBlock::createBackgroundShorthand #576
• [TASK] Deprecate DeclarationBlock::createListStyleShorthand #577
• [TASK] Deprecate DeclarationBlock::createBorderShorthand #578
• [TASK] Deprecate DeclarationBlock::createDimensionsShorthand #579
• [TASK] Deprecate DeclarationBlock::createFontShorthand #580