Drop users automatically into WeeChat instead of the shell (requires #27)

[RyanSquared]

Suggested and 👍'd by multiple people on IRC. Just need to change .tmux_bootstrap iirc to add a change to window 1.

[lrvick]

I don't know how I feel about this.

Then how will new users get to see the welcome message that explains where they are and how to navigate around?

Putting them directly into the welcome screen is intentional as it forces them to read in order to navigate anywhere else, as well as see our sponsorship/donation calls to action.

[RyanSquared]

This implies #27 is added for this reason