Add a custom variant name

[radvil]

Is your feature request related to a problem? Please describe.

I often find myself always tinkering my catpuccin color palettes, but at the same time I don't want to replace all of the default colors variant. It depends on the situation e.g. I am working on my low light room, I usually switch from mocha to frappe because frappe is more satisfying to work with. The problem is now I have my new color palettes for frappe, but I sometimes going back to my config to toggle them in order to get my default ones (again because I like it).

Describe the solution you'd like

I want a custom variant name to work with when i am focusing on work, rather then going back and forth to toggle my custom palettes. For example by simple calling vim.cmd("colorscheme catppuccin-custom1"),

Describe alternatives you've considered

I was thinking maybe you guys can provide some config similar to the following:

    custom_variants = {
      custom1 = {
        merge_from = "frappe",
        values = {
          maroon = "#ea999c",
          peach = "#ff9b5e",
        },
      },
      custom2 = {
        merge_from = "mocha",
        values = {
          maroon = "#ea999c",
          peach = "#ff9b5e",
        },
      },
    },

Additional context

This is my custom config override for frappe variant, I like the color contrast sometimes, but I don't want to override the default palette because I like all of the default variants palette.

Anyway, thanks for a good work!. I've been using catppuccin since I started to switch to neovim couple months ago.