Integrate script-running support akin to vscode-markdown-code-runner

[seltzered]

One of the challenges when using beancount is keeping various scripts (along with their command-line arguments) available to run easily. Sometimes these can be ones specific to user needs, and need to be easily run.

One way to facilitate easily finding and running them is through a 'code-runner' extension (such as https://github.com/JeepShen/vscode-markdown-code-runner ) paired with markdown file keeping user instructions. This extension is a decent start but could use some updates and/or could see something with further integration specific to Beancolage.

Alternatively some shortcuts could be written into the beancount file itself and parsed to show run buttons, by parsing certain 'custom' directives within the beancount file.

I'm aware Fava does facilitate an "Import" button configured via import-config, but from personal experience I've found the import process usually more interactive rather than fully-automated to make use of it.

Feature Description: