rewrote token implementation and added official cache support

[weinong]

Changes:

1. removed adal from all interfaces and replaced with azidentity
2. rewrote most credential flows using azidentity
3. enabled persistent cache for supported credential flows. For details https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/azidentity/TOKEN_CACHING.MD
4. every combination of credential flow is written in its own struct
5. added support to use PEM files for client certs
6. added http client to allow recording and playback and go-vcr based unit tests
7. migrated go-vcr to v4
8. added disabling instance discovery option to all azidentiy credentials
9. fixed a bug where authority host is not set correct in some environments

Breaking change:

1. Previous caching implementation is removed. Now we are using caching provided by azidentity. This also means any credential flows not implemented by azidentity will not have any caching. Notably, interactive with pop, device code with legacy and ropc with pop will NOT have cache.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 41.76471% with 693 lines in your changes missing coverage. Please review.

Project coverage is 54.41%. Comparing base (15edb67) to head (4f1f1d7).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/internal/testutils/govcrutils.go	0.00%	104 Missing ⚠️
pkg/internal/token/clientcertcredential.go	50.37%	51 Missing and 15 partials ⚠️
...nternal/token/usernamepasswordcredentialwithpop.go	0.00%	54 Missing ⚠️
pkg/internal/token/interactivebrowsercredential.go	0.00%	41 Missing ⚠️
pkg/internal/token/githubactionscredential.go	51.21%	32 Missing and 8 partials ⚠️
pkg/internal/token/execCredentialPlugin.go	11.90%	37 Missing ⚠️
pkg/internal/token/adalclientcertcredential.go	45.09%	27 Missing and 1 partial ⚠️
pkg/internal/token/clientcertcredentialwithpop.go	55.17%	23 Missing and 3 partials ⚠️
...kg/internal/token/clientsecretcredentialwithpop.go	51.85%	23 Missing and 3 partials ⚠️
pkg/internal/token/usernamepasswordcredential.go	44.68%	20 Missing and 6 partials ⚠️
... and 20 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #608      +/-   ##
==========================================
- Coverage   63.43%   54.41%   -9.03%     
==========================================
  Files          37       42       +5     
  Lines        2210     2354     +144     
==========================================
- Hits         1402     1281     -121     
- Misses        733      974     +241     
- Partials       75       99      +24     

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