:art: Improved the Jira Agile HTTP Client implementation.

[ctreminiom]

1. Created a new interface called Connector with only two methods.

2. Replacing the Client interface with 6 methods.

3. Added the possibility to return a dedicated error based on the http response on the Call method.

4. Changed the client interface from Client to Connector on the agile services.

5. Removed the unnecessary code from the service implementations.

[codecov[bot]]

Codecov Report

Merging #219 (828c2f1) into main (b6643b0) will increase coverage by 0.12%. The diff coverage is 95.23%.

@@            Coverage Diff             @@
##             main     #219      +/-   ##
==========================================
+ Coverage   85.53%   85.66%   +0.12%     
==========================================
  Files         137      137              
  Lines       11678    11625      -53     
==========================================
- Hits         9989     9958      -31     
+ Misses        942      931      -11     
+ Partials      747      736      -11     

Impacted Files	Coverage Δ
jira/agile/api_client_impl.go	84.00% <80.85%> (+2.66%)	:arrow_up:
jira/agile/internal/authentication_impl.go	100.00% <100.00%> (ø)
jira/agile/internal/board_backlog_impl.go	100.00% <100.00%> (+13.33%)	:arrow_up:
jira/agile/internal/board_impl.go	98.75% <100.00%> (+1.13%)	:arrow_up:
jira/agile/internal/epic_impl.go	100.00% <100.00%> (+6.89%)	:arrow_up:
jira/agile/internal/sprint_impl.go	95.12% <100.00%> (+4.58%)	:arrow_up: