Add custom_granularity_columns to TimeSpineSource

[courtneyholcomb]

Completes SL-2744

Add custom_granularity_columns to TimeSpineSource. Along the way:

• Bumped DSI version to get the new spec that includes custom granularities. Updated this in both MF and metricflow-semantics, since the spec was needed in both places. Now that mantle points to an older commit of MF, it should be fine to use a dev version here for now. We'll just need to update to a non-dev version if we ever need to update the commit that mantle is using.
• Updated the commit of dbt-core that we use for tests. This was needed to enable compatibility with DSI 0.7.0.
• Renamed old attributes that weren't specific enough to differentiate them from the new attributes.

[linear]

SL-2744 Update time spine interface in MF to use custom granularities

[tlento]

This seems reasonable at a glance but I'd like to come back to it after I make a bit more progress with the container object for managing custom granularities.

[courtneyholcomb]

This seems reasonable at a glance but I'd like to come back to it after I make a bit more progress with the container object for managing custom granularities.

@tlento any thoughts on merging this yet? Seems easy enough to change later!

[tlento]

Seems reasonable!