Fix error handling for http errors everywhere

[px-amaac]

• This commit adds check for response codes >= 400 on registration request and service configuration request and brings token request to use the same format
• Creates TYPE_HTTP_ERROR(5) in AuthorizationException
• Add method to create AuthorizationException of HTTP_ERROR type from http response code and message. Using HttpURLConnection.getErrorStream() to fill out errorDescription.
• Add tests for each area changed to handle a bad request http error.

This PR follows in line with what was done for #144 following Android documentation and Recommendations from Oracle on handling http error responses. The change in #144 did not address this issue in other places of the library and could potentially throw json exception if error stream does not contain a valid JSON response.

[codecov-io]

Codecov Report

Merging #496 into master will decrease coverage by 0.41%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master     #496      +/-   ##
============================================
- Coverage     83.71%   83.29%   -0.42%     
+ Complexity      479      477       -2     
============================================
  Files            42       42              
  Lines          2345     2364      +19     
  Branches        233      234       +1     
============================================
+ Hits           1963     1969       +6     
- Misses          299      314      +15     
+ Partials         83       81       -2

Impacted Files	Coverage Δ	Complexity Δ
.../java/net/openid/appauth/AuthorizationService.java	69.81% <100%> (-3.17%)	15 <0> (ø)
...nid/appauth/AuthorizationServiceConfiguration.java	87.91% <100%> (+1%)	10 <0> (ø)	⬇️
...ava/net/openid/appauth/AuthorizationException.java	72.97% <100%> (-1.18%)	18 <1> (-1)
...rary/java/net/openid/appauth/internal/UriUtil.java	70.68% <0%> (-1.73%)	16% <0%> (-1%)

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