Add combine subgroup codes

Creates combine files for subgroups. Also adds the housing metric into the overall combine files.

Subgroup combine programs follow the file list below:

[x] 11_construct_county_all
[x] 12_construct_county_race-ethnicity -- include race, race-ethnicity
[x] 13_construct_county_race-ethnicity -- race-share geography
[x] 14_construct_county_economic-well-being -- economically disadvantaged/not economically disadvantaged, income, extreme poverty/not extreme poverty
[x] 15_construct_county_age -- age group, youth age group
[x] 16_construct_county_gender
[x] 17_construct_county_tenure rent/own
[x] 18_construct_county_disability
[x] 19_construct_county_industry
[x] 20_construct_county_mothers-education

[x] 61_construct_place_all
[x] 62_construct_place_race-ethnicity -- include race, race-ethnicity
[x] 63_construct_place_race-ethnicity -- race share geography
[x] 64_construct_place_economic-well-being -- economically disadvantaged/not economically disadvantaged, income, extreme poverty/not extreme poverty
[x] 65_construct_place_age -- age group, youth age group
[x] 66_construct_place_gender
[x] 67_construct_place_tenure
[x] 68_construct_place_disability

Next steps:

UI-Research / mobility-from-poverty