Friendlier handling of default webhook values on bot launch

[christolis]

Description

I have noticed that when inexperienced people just getting started on the project go through all the hoops of cloning the repository, setting up their Discord bots, creating their test server, they end up compiling the code in IDEs like IntelliJ IDEA and assuming they just change the token on their config.json, there are stacktraces and errors thrown once they attempt to run the bot. Specifically:

    Caused by: java.net.URISyntaxException: Illegal character in path at index 0: <put_your_webhook_here>
            at java.base/java.net.URI$Parser.fail(URI.java:2995)
            at java.base/java.net.URI$Parser.checkChars(URI.java:3166)
            at java.base/java.net.URI$Parser.parseHierarchical(URI.java:3248)
            at java.base/java.net.URI$Parser.parse(URI.java:3207)
            at java.base/java.net.URI.<init>(URI.java:645)
            at java.base/java.net.URI.create(URI.java:930)

For the average software engineer, they would be aware that the program is still running and that the bot is ready, but two things:

• Someone who is not trained enough and is just starting to contribute will get thrown off by the error and potentially give up (I have experienced it happening)
• It's a generally better experience for knowledgable new contributors to set up the project effortlessly so that they can get started with contributing straight away without any stacktraces.

What I've done

This commit prints a friendly warning in the logger and no stacktrace in case the user has not updated the webhooks (which most of them will not have to, as they are primarily concerned with the Discord bot's token).

We hide the stacktrace in case there is a <put_your_webhook_here> value in the logInfoChannelWebhook and logErrorChannelWebhook configuration keys so that IntelliJ IDEA does not put the stacktrace in the spotlight and potentially scare new contributors.