Add the "getOrg" function to create Org type from HTTP response

This code is common to at least two functions, by moving this to a
specific function we can reuse the same code everywhere.
The page indice is an int, not int8

What we really want here is an int and use the Itoa function provided by
the strconv package to convert the integer to a string.
Rename getOrg to getOrgs

This function return a list of Org.
Add the getOrg function.

This function can be reused in at least two other functions.
Move the code to extract a list of team to its own function
Add the getTeam function
Check for error first then instantiate a type.

No need to instantiate a new type if we get an error while reading the
body from the HTTP response.
Apply gofmt to the org's source.
Return a boolean for the function CheckPublicOrgMembership

If the API is returning a valid status (204 or 404), return the
appropriate boolean value to the caller.