Rework design table and L1 column structure

[bpbond]

Our initial L1 data (v0-9) had a lot of information shoehorned into the "design_link" column. This column was a pain for users to parse; difficult to work with or update for us; and made it hard to spot mistakes.

This PR changes the design table structure so that individual columns encode information about

• Instrument - the overall measurement instrument (e.g., "AquaTROLL")
• Which - which specific AquaTROLL, etc.,
• Individual - either which experiment unit (e.g. tree) is being measured, or which named TEROS sensor, etc.
• research_name - as before, this describes the value column, i.e. what is being measured

In summary, this makes working with the design table easier for us, and working with the L1 data easier for everyone.

Old L1 data structure

New structure (this PR)

[bpbond]

When you get to this SP-

This is our last chance to change the L1 structure without breaking things--that is, when we declare it "v1-0", people will assume and expect that it's stable for a while.

With that in mind, we might want to consider changing some of the column names above:

• research_name - what about "Variable"?
• Instrument - any better ideas?
• Which - any better ideas?
• Individual - ?
• value - to "Value" (for consistent capitalization)?

Thx

[stephpenn1]

Okay - I'm running this on my computer so I can inspect each part and will give full feedback after

[bpbond]

@stephpenn1 Is it OK if we merge this and then deal with reworking columns ( #127 ) via a second PR? If you approve, that would be helpful, as I have some other changes that depend on this. Thanks

[stephpenn1]

We will revisit the new columns, approving this for now for merging

[bpbond]

Thank you!