Improved developer guide

[mm21]

Added a section in the developer guide on the command-line targets for development workflows: https://mm21.github.io/trilium-alchemy/dev/guide.html#command-line-targets

I think scons is nice for this sort of thing since you can easily handle dependencies. For example if you run scons badges to update the badges, it will also run the tests to generate reports if you haven't already done so.

[mm21]

Also, now you can pass --regression or --filter along with targets analysis, mypy, or pyright. This will run the analysis only on select files, with --regression using a list of files currently expected to pass. This list is maintained as REGRESSION_PATHS in SConstruct.