chore: make public api consistent

Summary:

Right now we have two ways to access the public api we have `require('ivy')`
and `vim.ivy. Each way has a different api that will cause some confusion.

Now both apis are the same so anyone that wants to integrate with ivy can do so
without having to figure out what one they need to use.

Test Plan:

The unit tests cover most of the work, I have also been using this locally for
quite some time now with now issues.

lua/ivy/controller.lua

@@ -1,9 +1,7 @@
 local window = require "ivy.window"
 local prompt = require "ivy.prompt"
-local utils = require "ivy.utils"
 
 local controller = {}
-controller.action = utils.actions
 
 controller.items = nil
 controller.callback = nil

lua/ivy/init.lua

@@ -1,11 +1,28 @@
 local controller = require "ivy.controller"
+local libivy = require "ivy.libivy"
 local config = require "ivy.config"
+local utils = require "ivy.utils"
 local register_backend = require "ivy.register_backend"
 
 local ivy = {}
+
+ivy.action = utils.actions
+ivy.utils = utils
+
+ivy.match = libivy.ivy_match
+
 ivy.run = controller.run
 ivy.register_backend = register_backend
 
+ivy.checkpoint = controller.checkpoint
+ivy.paste = controller.paste
+ivy.complete = controller.complete
+ivy.destroy = controller.destroy
+ivy.input = controller.input
+ivy.next = controller.next
+ivy.previous = controller.previous
+ivy.search = controller.search
+
 -- Private variable to check if ivy has been setup, this is to prevent multiple
 -- setups of ivy. This is only exposed for testing purposes.
 ---@private

plugin/ivy.lua

@@ -1,9 +1,9 @@
-local controller = require "ivy.controller"
+local api = require "ivy"
 
 -- Put the controller in to the vim global so we can access it in mappings
 -- better without requires. You can call controller commands like `vim.ivy.xxx`.
 -- luacheck: ignore
-vim.ivy = controller
+vim.ivy = api
 
 vim.paste = (function(overridden)
   return function(lines, phase)