read Migrate Technology files

[Rafnuss]

More widely, need to think of a more general system that works with any file type. Main idea is to focus the process on the data that are needed:

pam <- list(
    pressure=data.frame(date=c(), obs=c())
    light=data.frame(date=c(), obs=c())
    acceleration=data.frame(date=c(), obs=c())
    id=folder
)

Notes:

• we cannot assume that pressure, light or acceleration are on the same date
• same file might contains two variables
• date format might change.

⚠️ Replace act with obs everywhere (breaking change?) and remove pich