Adding auth0_pages data source

[willvedd]

🔧 Changes

In lieu of removing the auth0_global_client data source for the next major release (see: #704 , #691), we need to offer a data source that allows the retrieve custom login page. This PR compliments the the auth0_pages resource with a data source.

📚 References

Related PRs

• DXCDT-472: Add new auth0_pages resource #691
• DXCDT-450: Removing auth0_global_client resource #704

🔬 Testing

Added acceptance test.

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

Merging #706 (7f72713) into v1 (1168aaf) will increase coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##               v1     #706      +/-   ##
==========================================
+ Coverage   87.60%   87.61%   +0.01%     
==========================================
  Files          84       85       +1     
  Lines       13573    13586      +13     
==========================================
+ Hits        11890    11903      +13     
  Misses       1272     1272              
  Partials      411      411              

Impacted Files	Coverage Δ
internal/provider/provider.go	100.00% <ø> (ø)
internal/auth0/page/data_source.go	100.00% <100.00%> (ø)