Implement a way to edit postings note and status

[advy99]

This PR introduces a new option called "Posting details" with two choices, basic posting and detailed posting. When selecting basic posting, NanoLedger works as for now, and when selecting "Detailed posting", when editing a posting a new row for editing the posting note and status will appear on the selected row:

I also added the necessary parts in the parser to parse the posting status. For now I will set the PR as draft as I still need to write the parser tests.

Fixes #229

[chvp]

Hey, sorry for letting this sit for so long, I had a really busy february. To be honest, I'm not a huge fan of introducing yet another setting for this. Especially because it's one that I personally won't use. I'd prefer to redesign the posting rows a little bit to make space for an always-present expand button rather than introducing the setting...

[advy99]

Hi! Sorry for the delay. No problem from my part. If you want to keep the changes from the data storage and parsing part, I could modify the PR to delete all the UI and preferences things, just to keep everything else waiting for a UI redesign. On the contrary, if you think that is better to not introduce all this code until the feature is fully ready, feel free to close this PR.