Replace space in theme name with - or _

[AethanFoot]

Based on AethanFoot/leftwm-theme-dracula-rounded#1, the folder created for themes with a space in their title will also have a space in it. This causes string splitting with the default up and down scripts as $SCRIPTPATH is not double quoted, and is not ideal in general. I feel replacing the space with an _ when creating the folder would be best practice (also removing capital letters would be nice but not needed).

[mautamu]

We might want to follow the AUR package naming scheme :

Package names can contain only alphanumeric characters and any of @, ., _, +, -. Names are not allowed to start with hyphens or dots. All letters should be lowercase.

There are a couple different ways to get there:

• Renaming. We could just rename all of the packages in leftwm-community-themes and then write a function in leftwm-theme that can accept name changes, such as:

  [[changes]]
  type = "Rename"
  package = "Dracula Rounded"
  result = "dracula-rounded"
  action = "mv"

  The problem we'll likely see with this is people might use older leftwm-theme versions that would not yet support this and duplicate the package into two. I think implementing such a feature for future changes would be helpful, however.
• Style enforcement. We could instead enforce styles in leftwm-theme new, leftwm-theme update and leftwm-theme upgrade, and just update paths accordingly. We'd likely want to also make sure to re-link the current directory.

We could also do a combination thereof, and I suspect that's the direction we'll ultimately want to go. I will likely be a bit busy until May, so I'll add the "Help Wanted" label for now. I'll make a sample task list for anyone wanting to take on this project though (other steps might be necessary, just pitching what this might look like):

• Adopt a set style guideline and note this change in README.md
• Submit a PR to leftwm-community-themes changing all names to match the style requirements
• Write a function that can be called that will move old directory (probably accept either Path or PathBuf) to a new one that matches the name (see install for how that's done).
• Change installer to rename the folder to the guidelines. As install just wraps git clone, we should be able to rename, see StackOverflow and git2 docs.
• Add [[changes]] struct and ChangeType enum to config.rs. Likely similar to:

     enum ChangeType {
       Rename,
       Delete,
    }
     struct changes {
       id: UUID, //could also be an integer? 
       type: ChangeType,
       package: String,
       results: String,
       action: Option<String>
     }

• Implement a utility function (likely in config.rs) that can retroactively rename necessary themes.toml fields (name and directory).

If we put the [[changes]] struct at the top of known.toml, it may be that older versions of LeftWM will be unable to parse the document, which would prevent weird name bugs. However, I think tables have to be at the end of a struct so this might not be possible. Other solutions welcome!