Add JWT as default token for portals

[chamilaadhi]

This PR changes opaque tokens to JWT for portal logins

Note:
This pr needs to be merged after wso2-extensions/identity-inbound-auth-oauth#2384 and wso2/carbon-identity-framework#5547

After these PRs, Need to add following to the deployment.toml to enable JWT for portals

  [apim.oauth_config]
  enable_jwt_for_portals = true
  
  [transport.https.properties]
  maxHttpHeaderSize = "12288"
  
  [oauth]
  add_tenant_domain_to_access_token = true

[codecov]

Codecov Report

Attention: Patch coverage is 5.45455% with 52 lines in your changes are missing coverage. Please review.

Project coverage is 47.49%. Comparing base (4900ea0) to head (bc3869d).
Report is 86 commits behind head on master.

❗ Current head bc3869d differs from pull request most recent head ec75e45. Consider uploading reports for the commit ec75e45 to get more accurate results

Files	Patch %	Lines
...rbon/apimgt/rest/api/admin/v1/dto/SettingsDTO.java	0.00%	9 Missing ⚠️
.../apimgt/rest/api/publisher/v1/dto/SettingsDTO.java	0.00%	9 Missing ⚠️
...rbon/apimgt/rest/api/store/v1/dto/SettingsDTO.java	0.00%	9 Missing ⚠️
.../rest/api/util/impl/OAuthJwtAuthenticatorImpl.java	0.00%	9 Missing ⚠️
...ava/org/wso2/carbon/apimgt/impl/utils/APIUtil.java	0.00%	6 Missing ⚠️
...rest/api/dcr/web/impl/RegistrationServiceImpl.java	28.57%	4 Missing and 1 partial ⚠️
...imgt/rest/api/dcr/web/dto/RegistrationProfile.java	33.33%	2 Missing ⚠️
...i/admin/v1/utils/mappings/SettingsMappingUtil.java	0.00%	1 Missing ⚠️
...lisher/v1/common/mappings/SettingsMappingUtil.java	0.00%	1 Missing ⚠️
...est/api/store/v1/mappings/SettingsMappingUtil.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #12297      +/-   ##
============================================
+ Coverage     42.00%   47.49%   +5.49%     
- Complexity     3265     4142     +877     
============================================
  Files          1838     1839       +1     
  Lines        135618   135715      +97     
  Branches      19588    19608      +20     
============================================
+ Hits          56967    64462    +7495     
+ Misses        71787    63683    -8104     
- Partials       6864     7570     +706     

Flag	Coverage Δ
integration_tests	42.22% <5.45%> (+6.87%)	⬆️
unit_tests	20.55% <0.00%> (-0.01%)	⬇️

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