Add more customization to `Api` class methods

[aik099]

Current situation:

1. the Jira API endpoints have a vast set of supported parameters (for POST requests there is a possibility to specify also GET parameters)
2. the Api class methods that perform GET Jira API calls provide limited configurability, e.g.
   • only several common parameters can be specified
   • sometimes there is $params parameter for specifying additional query params
3. the Api class methods that perform POST Jira API calls provide limited configurability, e.g.
   • only several common parameters can be specified
   • sometimes there is $params parameter for specifying additional POST data
   • no way to specify query parameters

This has resulted in some issues:

• The "Api::getProjects" needs to allow specifying "expand" #154
• The "Api::getIssue" call ignores "$expand" #153

Solution

1. Support passing of query string parameters in API calls #220
2. Using builder pattern & fluid interface #223