v4

[hermanho]

1. Support .Net7, .Net 8
2. Remove support .Net 6 and lower version
3. Support Hangfire and JSON.Net serialization
4. Remove obsoleted codes

[github-actions]

Test Results

79 tests  +2   79 ✅ +2   5s ⏱️ ±0s
 2 suites ±0    0 💤 ±0 
 2 files   ±0    0 ❌ ±0 

Results for commit c21e5a6. ± Comparison against base commit fbdc277.

This pull request removes 1 and adds 3 tests. Note that renamed tests count towards both.

Postal.EmailTests ‑ Derived_Email_sets_ViewData_Model

Postal.EmailParserTests ‑ Same_image_embedder_in_life_cycle
Postal.EmailViewRenderTests ‑ Render_with_correct_emailviewdir
Postal.Tests.Integration.IntegrationTests.EmailViewTests ‑ Get_EmailTemplateWith_UrlHelper2

♻️ This comment has been updated with latest results.