Add missing type hints - Part 1 (#4775)

* add missing type hints to application code

* add typehints to tests.config, tests.console.commands.debug, tests.console.commands.env

* add typehints to tests.console.commands.plugin

* add typehints to tests.self

* add typehints to tests.console.commands.source

* add typehints to tests.console.commands.about

* add typehints tests.console.commands.add

* add typehints to tests.console.commands.test_cache

* add typehints to tests.console.commands.test_check

* add typehints to tests.console.commands.test_config

* add typehints to tests.console.commands.test_export

* add typehints to tests.console.commands.test_init

* add typehints to tests.console.commands.test_install

* add typehints to tests.console.commands.test_lock

* add typehints to tests.console.commands.test_new

* add typehints to tests.console.commands.test_publish

* add typehints to tests.console.commands.test_remove

* add typehints to tests.console.commands.test_run

* add typehints to tests.console.commands.test_search

* add typehints to tests.console.commands.test_show

* add typehints to tests.console.commands.test_version

* add typehints to tests.console.test_application

* add typehints to tests.console.conftest

* add typehints to tests.console.conftest

* add python version constraint for typing-extension

* fix type hint for http fixture