healthcheck: refactoring, remove deprecation wanings (#35)

* refactor(checkhealth): remove deprecation warnings, complete rewrite

* refactor(checkhealth): rename util file

* style(healthchecker): reformat lua in vim file

* refactor(health): move all report function into table

lua/gopher/_utils/health.lua

@@ -0,0 +1,17 @@
+return {
+  ---@param lib string
+  ---@return boolean
+  lualib_is_found = function(lib)
+    local is_found, _ = pcall(require, lib)
+    return is_found
+  end,
+
+  ---@param bin string
+  ---@return boolean
+  binary_is_found = function(bin)
+    if vim.fn.executable(bin) == 1 then
+      return true
+    end
+    return false
+  end,
+}