fix(templates): Correct gating logic for vimrc

There are a couple of code blocks in vimrc.j2 that are intended to be gating logic, for example:

 {% if vim['options'] %}

However, this causes Jinja to attempt to retrieve the key options inside the variable vim. This gating logic can fail in the even that somehow this is an empty list or None, but the intention of the logic is to check to see if vim has the key options. This changes it so the gating logic looks like this:

 {% if 'options' in vim %}

Thus, it allows for better gating of code blocks and keeps the templating from erroring out in even that there are no options, remaps, or bundles.

Signed-off-by: Patrick Wagstrom patrick@wagstrom.net