Support enabling/disabling key mappings

[hcgatewood]

General information

- Terminal program: iTerm.app 3.5.9 (xterm-256color)
- Operating system: macOS 14.7.1 (23H222)
- ZSH framework: oh-my-zsh master (7ed475cb)
- ZSH version: zsh 5.9 (x86_64-apple-darwin23.0)
- ZVM version: zsh-vi-mode 0.11.0 

Basic examination

• [x] I have read through the README page
• [x] I have the latest version of zsh-vi-mode
• [x] I have tested with another terminal program

Problem description

I have the following zsh keymappings, which are overridden by this plugin due to its lazy loading. I would like to keep the lazy loading on for startup time's sake, so I would like a config option to disable the plugin's default ctrl-n/ctrl-p keybindings.

# Better forward/backward search
bindkey "^[[A" up-line-or-beginning-search
bindkey "^[[B" down-line-or-beginning-search
bindkey "^p" up-line-or-beginning-search
bindkey "^n" down-line-or-beginning-search

Reproduction steps

1. Type some prefix to a previous command
2. Hit ctrl-p
3. Observe that the chosen history command is just "most recent", not "most recent matching prefix"

Expected behavior

I would like to be able to disable the plugin's ctrl-p/ctrl-n keybindings, such that the "most recent matching prefix" works as expected