Extra access to the Reminders tool

[ajtruckle]

Is your feature request related to a problem? Please describe.
Meeting Schedule Assistant has a Reminders tool:

And Public Talks has a similar Journal feature:

Describe the solution you'd like
The Reminders window can be displayed from here:

• Main application window.
• Meeting Editor

I propose that we add direct access to the Reminders feature from these windows too:

• Assignments Editor
• Weekend Meeting Editor

Additional context
I did wonder if the Away Talk window should have direct access to the journal too. But I am not sure. 🤔 This is because the Public Talks Journal has some different features:

Compared to the Meeting Schedule Assistant Reminders (note that reminders show on the calendar by design):

[ajtruckle]

I've opted for a new approach to Public Talk reminders. Now, each public talk includes an Exchange Notes text field.

See: #101