feat: in-code specification of logging settings

[tarbomb]

Notice

• I understand the code that I have edited, and have the means
  to test it before making changes to Concord.

What?

Add in-code specification of logging settings like logging level, filename, etc.

Why?

To satisfy issue #100

How?

I have done this by introducing two new main things:

• A new structure (discord_settings)
• A new function (discord_settings_init)

The discord_settings structure will hold all of the in-code settings that should be used to
initialize a new client, while discord_settings_init function will apply those settings and
initialize a new client.

Testing?

Currently, I have not written any sanity checks for the contents of the settings array. That will be done
at a later time.