Major config changes

Add alacritty config, as it is my main terminal now
Change **a lot** of nvim configs
Add tmux configuration
Update zsh configs
Add .gitconfig with custom pager
Include tmux-plugin-manager as a submodule

.config/nvim/lua/plugins/tmux-nvim.lua

@@ -0,0 +1,7 @@
+-- return {
+--   'aserowy/tmux.nvim',
+--   event = "VeryLazy",
+-- }
+return {
+  "numToStr/Navigator.nvim",
+}