WIP: Allow all extensions in links

[tshort]

It's nice to be able to link to more types of files than the default. That could be code (py, js, sh), data (csv), configuration files (yaml), or anything else.

This fixes #592 and #593.

I've tried this out, and it works well. It's WIP because:

• If this approach is desired, the extension code probably needs some work. There's no need for otherExts. The code could treat extensions as one of: markdown, images, and everything else.

• I assume tests need to be update.

[svsool]

Hi @tshort, currently all extensions are not allowed for performance reasons (workspace cache is rebuilt on restart), for example, there could be users where knowledge base is located next to deeply nested folders like node_modules with lots of files. Another suggestion could be to allow custom extensions to be configurable via settings or if all are needed allow a wildcard like *.

[tshort]

I'll play around with configurable options.