Add --flat option for database syncs

[oliverkaiser]

Added --flat parameter for database syncs, preventing nesting of pages. This is useful if you have a larger set of MD files in a folder but want to have all of them as single entries in your database instead of nested child pages. So you can filter through all the documents e.g. via their properties.

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[oliverkaiser]

• added --flat option for database syncs, avoiding nested pages.

[Myastr0]

First thank you for your contribution on mk-notes project ! 🙌

Please can you provide a pull request description using the PR Description template file and explain a bit more what your changes are doing on mk-notes behavior 🙇‍♂️

[Myastr0]

I left you few comments on your PR, can you also add a new entry in the /docs sub projet to explain the new --flat behavior 🙇‍♂️

[oliverkaiser]

@Myastr0 done :) Sorry for some Ai mess, I am not really an engineer anymore and now AI helps me a lot to do some smaller things like these where I have gaps. Tried to follow your structures as best as possible.

[Myastr0]

Hey @oliverkaiser, thanks for the ping, I worked the previous days on mk-notes to rework globally the architecture of the project and made it more stable for next updates/improvment like yours ! (cf #69)

Until I merge this global refactor, I'll use this PR to implement the --flatten option on the new system, sorry for the delay, and thank you again for your contribution !

[Myastr0]

Hey @oliverkaiser , I release a new version of mk-notes that include your (reworked) proposal in the v3.2.0.

You can check the documentation to know how to use the new --flat option which is highly inspired by this proposal !