Update curl.md with /getConfig endpoint

[khanjasir90]

Recently /getConfig endpoint was added . Update the curl.md file with the /getConfig endpoint.

[khanjasir90]

@Namyalg I am working on this!

[Namyalg]

Sure, go ahead

[clintonMF]

@Namyalg can I work on this

[Namyalg]

@khanjasir90 are you working on this issue?

[clintonMF]

There are various files that the /getConfig endpoint can get from the input folder. @Namyalg which specific ones would you advice I write curl command for? I was thinking about the files below
config=localdomain.json
config=pools_cbm.json
config=modules_cbm.json
config=modules_output.json
config=spinup.json
config=variables.json
config=internal_variables.json

[khanjasir90]

@clintonMF you can go ahead with this since I am busy with some college work :)

[clintonMF]

Thank you very much @khanjasir90