[Backport] [2.x] Add import ordering to Spotless formatting rules (#3666)

[reta]

Backport of #3666 to 2.x

[codecov]

Codecov Report

Merging #3667 (2ea7b92) into 2.x (ea0d4ff) will increase coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                2.x    #3667      +/-   ##
============================================
+ Coverage     64.82%   64.84%   +0.01%     
- Complexity     3620     3622       +2     
============================================
  Files           285      285              
  Lines         20496    20496              
  Branches       3382     3382              
============================================
+ Hits          13286    13290       +4     
+ Misses         5530     5528       -2     
+ Partials       1680     1678       -2     

Files	Coverage Δ
...ic/auth/http/jwt/AbstractHTTPJwtAuthenticator.java	57.95% <ø> (ø)
...mazon/dlic/auth/http/jwt/HTTPJwtAuthenticator.java	75.51% <ø> (ø)
...byoidc/HTTPJwtKeyByOpenIdConnectAuthenticator.java	91.66% <ø> (ø)
...azon/dlic/auth/http/jwt/keybyoidc/JwtVerifier.java	79.62% <ø> (ø)
.../dlic/auth/http/jwt/keybyoidc/KeySetRetriever.java	80.00% <ø> (ø)
.../auth/http/jwt/keybyoidc/SelfRefreshingKeySet.java	57.74% <ø> (ø)
...ic/auth/http/kerberos/HTTPSpnegoAuthenticator.java	0.00% <ø> (ø)
...azon/dlic/auth/http/kerberos/util/JaasKrbUtil.java	0.00% <ø> (ø)
...dlic/auth/http/saml/AuthTokenProcessorHandler.java	50.28% <ø> (ø)
...zon/dlic/auth/http/saml/HTTPSamlAuthenticator.java	67.36% <ø> (ø)
... and 135 more

... and 1 file with indirect coverage changes