Add getLastKnowPosition

[miquelgall]

Is your feature request related to a problem? Please describe.
Following the documentation available here

https://docs.oracle.com/en/cloud/saas/field-service/cxfsc/op-rest-ofsccore-v1-resources-custom-actions-lastknownpositions-get.html

Add the call to the API getLastknowPosition

Describe the solution you'd like
include the call to the API, adjust the readme.md to include all the calls available in the code and add the right tests cases.