feat: initial implementation

A first working, publishable version of colorsaver.nvim.

This plugin connects to the ColorScheme event to detect changes to the
colorscheme. Any time that changes, it saves the colorscheme's name to a
local file. In addition to that, it can watch that local file for
changes. This way, when one `nvim` process changes the colorscheme, all
other instances will automatically reload the colorscheme.

.stylua.toml

@@ -0,0 +1,3 @@
+indent_type = "Spaces"
+indent_width = 2
+column_width = 100