Mbox with gchat

[ke4roh]

I extracted messages and google chat from gmail, and had to make these changes to get it to work for me.

I also added the time of the message to the export in a separate commit (same PR, but at least that way it's easier to split the two).

[jarrodparkes]

@ke4roh please take a look at #16 that incorporates your changes and extracts them into a .env file