Nvim: restructure all plugins configuration

.config/nvim/after/plugin/themer.rc.lua

@@ -1,11 +0,0 @@
---require("themer").setup({
---    colorscheme = "scery",
---    enable_installer = true,
---    styles = {
---        ["function"] = { style = 'italic' },
---            functionbuiltin = { style = 'italic' },
---            variable = { style = 'italic' },
---            variableBuiltIn = { style = 'italic' },
---            parameter  = { style = 'italic' },
---    },
---})

.config/nvim/after/plugin/themer.rc.lua

@@ -0,0 +1 @@
+../available/themer.rc.lua