feat: move all lua api into api module

lua/gopher/api.lua

@@ -0,0 +1,26 @@
+local API = {}
+local tags = require "gopher.struct_tags"
+local tests = require "gopher.gotests"
+local cmd = require "gopher._utils.commands"
+
+API.install_deps = require "gopher.installer"
+API.tags_add = tags.add
+API.tags_rm = tags.remove
+API.impl = require "gopher.impl"
+API.iferr = require "gopher.iferr"
+API.comment = require "gopher.comment"
+API.test_add = tests.func_test
+API.test_exported = tests.all_exported_tests
+API.tests_all = tests.all_tests
+
+API.get = function(...)
+  cmd("get", ...)
+end
+API.mod = function(...)
+  cmd("mod", ...)
+end
+API.generate = function(...)
+  cmd("generate", ...)
+end
+
+return API