#3231 step 4: Remove all setup functions

[alex-courtis]

Part of #3231 : Performance: Load Only Necessary Modules On setup and requiring API

This MUST be broken into multiple PRs: logical groups such as git or individual modules. There is a high blast radius and fast revert must be available.

Module setup should not be invoked at nvim-tree setup time, as they require the world which is expensive.

They should use the config module created in #3256

The setup function should be completely removed. In the case of any config being mutated such as system-open setup, it should be moved to the config module, executed at setup time.

Scope at c07ce43

rg -l "function.*\.setup\(opts\)" lua

• actions/fs/*
• actions/node/*
• actions/root/*
• actions/tree/*
• buffers.lua
• diagnostics.lua
• explorer/watch.lua
• git/*
• help.lua
• keymap.lua
• lib.lua
• notify.lua
• renderer/components/*
• view.lua
• watcher.lua