Friendly import names mapping to Drive files

[jpolitz]

We've gotten enough stumbles from users trying to make their own starter files related to Bootstrap that we should add a feature for this.

The proposal is to add a new kind of import where, in CPO configuration, a list of friendly names like bootstrap-ds-2022, dcic-2022, are mapped to Google Drive IDs.

This could be written in one of two ways:

• include bootstrap-ds-2022
• include curriculum("bootstrap-ds-2022")

The latter is a little more future-proof and honest about what's going on. The former is easier to type but requires a bit of a weird split in semantics between things written with the same syntax; import statistics doesn't go to Google Drive but import bootstrap-... does.