Trait for scripts

[sij1nk]

Currently, to implement a plsdo script, we must:

• have a source file within the scripts folder - this also defines the name of the script
• implement the run and command functions within the file with specific signatures
• register it by including it in the define_scripts macro invocation

This works ok for now, but I might prefer a more descriptive and explicit approach that uses a trait as a contract for the run and command fns, and removes the need for having to name files and place them into folders in a specific and unexplained way.

[sij1nk]

Transferred issue to local neorg notes