Refactor neovim config file structure

All plugins are now in their own files with their lazy specifications
and configurations. Also moved lazy initialization to init.lua because
it is very compact now

home/.config/nvim/lua/plugins/mason.lua

@@ -0,0 +1,57 @@
+-- Package manager for LSP servers, DAP adapters etc.
+return {
+  "williamboman/mason.nvim",
+  dependencies = {
+    "neovim/nvim-lspconfig",
+    "williamboman/mason-lspconfig.nvim",
+    "WhoIsSethDaniel/mason-tool-installer.nvim",
+    "mfussenegger/nvim-jdtls",
+  },
+  config = function()
+    require("mason").setup()
+
+    local mason_lsp = require("mason-lspconfig")
+    local lsp_utils = require('lsp_utils')
+    local capabilities = lsp_utils.get_capabilities()
+    mason_lsp.setup()
+
+    mason_lsp.setup_handlers({
+      -- Default handler
+      function(server_name)
+        require("lspconfig")[server_name].setup({
+          on_attach = lsp_utils.on_attach,
+          capabilities = capabilities,
+        })
+      end,
+
+      -- Override lua_ls settings
+      ["lua_ls"] = function()
+        require("lspconfig").lua_ls.setup({
+          on_attach = lsp_utils.on_attach,
+          capabilities = capabilities,
+          settings = {
+            Lua = {
+              runtime = {
+                -- Tell the language server which version of Lua you're using (most likely LuaJIT in the case of Neovim)
+                version = "LuaJIT",
+              },
+              diagnostics = {
+                -- Get the language server to recognize the `vim` global
+                globals = { "vim" },
+              },
+              workspace = {
+                -- Make the server aware of Neovim runtime files
+                library = vim.api.nvim_get_runtime_file("", true),
+              },
+              -- Do not send telemetry data containing a randomized but unique identifier
+              telemetry = { enable = false },
+            },
+          },
+        })
+      end,
+
+      -- Don't set up jdtls, it is set up by nvim-jdtls
+      ["jdtls"] = function() end,
+    })
+  end,
+}