Move lsp config to local file structure

.config/nvim/lsp/solc.lua

@@ -0,0 +1,17 @@
+---@brief
+---
+--- https://docs.soliditylang.org/en/latest/installing-solidity.html
+---
+--- solc is the native language server for the Solidity language.
+
+local util = require 'lspconfig.util'
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'solc', '--lsp' },
+  filetypes = { 'solidity' },
+  root_dir = function(bufnr, on_dir)
+    local fname = vim.api.nvim_buf_get_name(bufnr)
+    on_dir(util.root_pattern('hardhat.config.*', '.git')(fname))
+  end,
+}