Specific month and day doc type aliases used when creating

[LottePitcher]

Hey @D-Inventor!

I am raising this as a draft PR in case you have any input on the approach I'm taking for issue https://github.com/Infocaster/Datefolders/issues/3.

I have got as far as updating the code for the creation of new items. My next step is to update the code for the saving of existing items, and then finally to check the two recycle bin related notification handlers.

This has been tested on a v11 site, both with the new feature (i.e. with MonthFolderDocType and DayFolderDocType options configured) and without (i.e. the way you had previously).

Whilst I've been working on this I also did a bit of consolidating of the readme instructions:

• There were a couple of rogue 'DateFolderDocType' entries (should be 'FolderDocType')
• I changed the example ItemDocType alias to 'blogpost' as the AllowedParentDocTypes is set to 'blog'. I think blog posts are also a more likely use case than someone using it for a generically named doc type such as 'contentPage'

I checked Infocaster's contributing guidelines: there isn't a contrib branch on this repo so I assumed v11/develop was the one to branch from 🤞

[D-Inventor]

I love it, looking good so far!

v11/develop is a good branch to work from. When this pull request is merged, I can port it to other versions as well.

[LottePitcher]

Thanks @D-Inventor for such a prompt review! I shall keep going!