Create function to return station metadata

[lilyclements]

This PR should fix issue #50

@ChrisMarsh82 did you want to review this before I merge it in?

We do not have definitions or metadata for Malawi, this only returns for Zambia. Before testing, ensure that you have updated epicsadata

devtools::install_github("IDEMSInternational/epicsadata")

Then examples to test -

station_metadata(country = "zm", station_id = c("1", "33"), include_definitions = TRUE)

station_metadata()

[lilyclements]

@ChrisMarsh82 to add - the failed test is from the issue we were having with the json file. I can confirm the other tests run fine on my machine. The json file problem is something I will investigate.

[lilyclements]

@ChrisMarsh82 to add - I* managed to solve the problem with the tests always failing due to the json file. So, you can ignore my above statement! :D

*with the help of ChatGPT.

Look at those green ticks!