Add documentation for error handling best practices

[jmcook1186]

Sub of #655

What
Add documentation about our new error handling options

Why
As a developer I want to conform to the IF best practices for error handling when I build plugins.

Rationale
We are overhauling our error handling processes as part of our QA epic. This includes errors that surface from plugins. We will be applying the new standards to our IF maintained plugins, but we should also provide clear documentation for community developers so they can do the same if they so choose.

SoW

• Update plugin builkder guide to explain if-core and error class protocols
• Update builtin READMEs to explaint he errors emitted by each builtin

Size

M

[zanete]

Blocked as we haven't decided that the best practices are yet

[zanete]

Make sure you also handle timestamps and duration validation as per #466 and then create an issue per built-in plugin to confirm that they conform to the best practices

[zanete]

blocked by #593 and might also be covered by it, need to verify

[zanete]

@narekhovhannisyan @manushak please take a look at the PR