Define cookie prefix in one location

[dalelotts]

All cookies have a en- prefix, for epic-notes.

Consider allowing the user to define the prefix

When I implemented cookie consent I used the cookie category as the prefix so it was trivial to expire that category of cookie when consent was revoked.

[kentcdodds]

Hi @dalelotts,

How would you see that working? Would it be a question we ask during initial setup or a config-based thing? I really would prefer to avoid config-based things for the same reasons mentioned here: #526 (comment)