WIP: Crude first attempt to use &str's instead of Strings

[jleibs]

What

First pass of making the code-gen system use &strs instead of needing to copy all the strings. Also paves the way for using references on other array-types as necessary.

Big complication to resolve now is how to handle these reference lifetimes when it comes to interacting with the store.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested demo.rerun.io (if applicable)

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[jleibs]

Was obsoleted by: #2931