Better Templates + `rectx template` command functionality

[hrszpuk]

Is your feature request related to a problem? Please describe. The current template system is in still in development, but for the purposes of getting a fully-working product some features of the system are going to be neglected. This issue is going to highlight the features that still need adding so I don't forgot ;).

Describe the solution you'd like Here's a list of the features:

• [x] #50
• [x] rectx template test sub-command for testing custom templates. Should parse and generate the template file in a temporary directory. Errors will be printed to stdout so template creators know where issues in their templates are.
• [ ] Template binder to check if a folder has been created prior to a file or folder being placed within it. This just involves going through the parsed statements and keeping track of what's been generated and what hasn't.
• [ ] Meta-variable parsing with file content during project generation.
• [x] #51
• [x] #53
• [x] Add rectx template rename <name> <newname>: renames a template. Pretty straight forward tbh.
• [x] Add rectx template setDefault <name> : set a different template to be the default template generated.
• [x] Add rectx template test <path>: this will test the template by using it to generate a project structure in a temporary directory. This command will search all templates in templates/ before searching by path. This allows users to test if an installed template is working.
• [x] Add rectx template snapshot <path>: When provided the path to a folder, this command will walk through everything in the folder and generate a .rectx.template file that can be edited. This is a fast way of creating templates as the user simply creates the template structure with files/folders and rectx does the heavy lifting.
• [x] Add rectx template add <path>: Adds a template to the template/ directory.

Additional context Original template pull request: #40

[hrszpuk]

This won't be worked on until the current development branch has been merged into master.

[hrszpuk]

I forgot about metavariables, I will add those to the list as well.

[hrszpuk]

Will rename "setDefault" to just "default" because camelCase on the command line is kinda weird... :/

[hrszpuk]

Probably going to set up statement checking and metavariable replacement during a refactor since I think I can separate the lexer and parser then place them inside a generator struct (composition) which will be a nicer abstraction.