feat: add keymaps to options

[samirettali]

Add options to map keys for requesting, accepting and clearing suggestions.

There are a couple of thing I'm not 100% sure how to handle in a correct way like <tab>/<c-i> and fallback for <esc> when mapped in normal mode.

Also, this assumes all keymaps in normal mode, should it be possible to map keys in all modes using options?

Maybe something like blink.cmp does:

keymaps = {
 ["n"] = {
   ["<tab>"] = { "jump_or_accept", "fallback" }
   ["<esc>"] = { "clear", "fallback" }
 }
}

The only breaking change as for now would be the debounce option.

[tris203]

Thanks for the contribution

However, I don't really want to go down this path of configuring keymaps etc in the plugin

I cant think of a strong advantage of this method of configuration