Feature/event manager subscriber task stack size

[finger563]

Description

• Updated add_subscriber method of EventManager to allow setting the subscriber task stack size (only sets the stack size when creating the task, which only happens on first subscriber for a given topic).
• Rebuild docs

Motivation and Context

Right now the task size for the subscriber tasks was hardcoded to 8K - which is unnecessarily wasteful in some cases, but not enough in others. This PR adds a stack_size_bytes parameter (default to the original setting of 8K) which allows subscribers to set the task size.

NOTE: this configuration only has an effect for the first subscriber on a given topic (because it's only at that time that the task for the subscription is created).

How has this been tested?

Building the event manager example.

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Hardware (schematic, board, system design) change
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• I have updated the .github/workflows/build.yml file to add my new test to the automated cloud build github action.
• All new and existing tests passed.
• My code follows the code style of this project.