Refactoring hard-coded frontend route keywords

[katiefenn]

issue #4519

• Added configurable route keywords
• Replaced instances of hard-coded keywords with config
• Added keywords to frontend tests stub config

[ErisDS]

Hey @katiefenn, so sorry that it took me such a long time to get to this. I've both read through the code and taken it for a spin, and it's looking great.

I think keeping it in the config for now is OK as it's not possible to set it through the config.js. Eventually I think this would be set through the database settings or some such, which will mean dynamically loading it, but this PR means we can solve that problem separately.

One super nit-picky comment is that in some places config.routeKeywords gets repeated a lot, it'd be my personal preference to have a slightly shorter name or store a local variable to make it a bit shorter - but I don't have a good suggestion for a better name and it's not really an issue.

That just leaves me to ask if you could please update the commit message to match the preferred format?

[ErisDS]

Hey @katiefenn, I know you've been busy building your new Ghost site, so I have fixed up the commit message and merged this into master manually :)

💃