fix: enforce snake case app name

[Pebkac03]

Checks if app name is snake_case when running: stacked create app. Fixes Stacked-Org/stacked#1081.

1. If app name is snake_case behaviour is unchanged.
2. If app name is not snake_case then user is prompted with <originalAppName> is not snake_case as required by dart, did you mean <appName?> [Y/N]. If they answer yes then the app name will be changed, if they answer no then the program will throw and exit with the message: error: project name not snake_case.

[Pebkac03]

Marked as draft. Want to validate all rules for valid Dart app names as well as make the code cleaner.

[KickNext]

If use stacked create app . create started in current path, but fail with app name: . in current version. Should this be excluded or used as the name of the parent folder? This can be taken into account in this fix.

[Pebkac03]

@nikitiser do you mean the version of this PR or the current version of Stacked? If you found an issue you feel this resolves please file an issue referencing this PR.

If you mean this PR, could you please clarify?

[Pebkac03]

If use stacked create app . create started in current path, but fail with app name: . in current version. Should this be excluded or used as the name of the parent folder? This can be taken into account in this fix.

Thanks for the clarification, should be fairly simple to implement. I'll add it to this PR tomorrow and we can decide to either keep it or split it out before merging.

[Pebkac03]

Oh, @nikitiser. A question, would you expect it to only work in an empty folder or one with stuff already added. The latter would be a lot bigger of a task and might be better implemented as a new stacked init command.

[KickNext]

@Pebkac03 I meant in an empty folder. If it is not empty, there should probably be an error for stacked create app . command.

[Pebkac03]

Alright, will add an error for that case as well. Thanks for the hasty reply!

[Pebkac03]

Sorry for the late reply but when digging deeper I found a flaw in the logging. The CLI currently only logs process.stdout and not process.stderr when running commands. In short, it logs info to the terminal but not error messages. I have a working implementation not commited yet but since it's a bigger change affecting all commands it needs more discussion and work.

Will commit when i can so anyone can look through it.

[Pebkac03]

Closing this in favour of #57. Will look into adding stacked create app . @nikitiser