Make variable names more descriptive

[lwjohnst86]

E.g. the variables bed_q_* in bedq don't actually describe anything and requires you to read the description. These need to be improved on.

[lwjohnst86]

There's others like contact_reason___* with numbers for the end that are also not helpful.

[lwjohnst86]

Others are sglt2_type_rep___* along with similar columns in that resource/table.

[signekb]

onlimit-study/feasibility-data#183 is related to this as well.