+ Package manager: paq-nvim

+ added `<leader>p` mapping for paq to:
    + install
    + update
    + clean

+ added plugins directory
    * but not `require`d by default

+ updated README w/ paq install info

lua/plugins/init.lua

@@ -0,0 +1,8 @@
+require "paq" {
+    "savq/paq-nvim"; -- Let Paq manage itself
+
+    "neovim/nvim-lspconfig";
+    "hrsh7th/nvim-compe";
+
+    --{"lervag/vimtex", opt=true};
+}