Split initialization of sms provider and hlr lookups provider

[Spring3]

I needed only HLR lookups provider, so I called getProviders() function to get one, but the thing is that it also initializes SmsApiProvider inside and hence requires some envs to configure that one.

So I needed to use random values as stubs to avoid assertion error when it tried to initialize SmsApiProvider, but this polluted the env file with some unused stubs.

I think providers should be initialized separately and the function should be split in two

UPD: for backward compatibility you can keep getProviders function that will call those 2 new functions after a separation of concerns

[Spring3]

Closing this as it can be achieved by importing the required hlr lookup class directly out of the library

[mrister]

There is an underlying issue here because the Library is dependent on env vars when it should take in arguments for providers o reopening to not forget to solve it.