Prettier error messages for specific, common installation problems

[seanccsmith]

When the mysql user specified in the .env file does not have the correct permissions to access the _zermelo_cache table and/or _zermelo_config table, we get the following verbose stacktrace error:

What we want is to implement a try/catch structure to see if the user can see these tables. If they cannot, the browser should display a simple page containing only the text:

"The (insert mysqlusername here) mysql user does not have permissions to the (databaes for _zermelo_cache and _zermelo_config gotten from the config file). You need to enable this access before moving forward."

When composer require zermelo_installer has been run, but php artisan zermelo:install has not been run, currently we get a similar verbose stacktrace message, and want instead an analogous simple page with just the text:

"Zermelo has not been installed. Please run ./artisan zermelo:install in your project root directory."