Chore: Refactor OAuth/social package to service (#35403)

* Creating SocialService

* Add GetOAuthProviders as socialService method

* Add OAuthTokenService

* Add GetOAuthHttpClient method to SocialService

* Rename services, access socialMap from GetConnector

* Fix tests by mocking oauthtoken methods

* Move NewAuthService into Init

* Move OAuthService to social pkg

* Refactor OAuthService to OAuthProvider

* Fix nil map error, rename file, simplify tests

* Fix bug for Forward OAuth Identify

* Remove file after rebase

pkg/setting/setting_oauth.go

@@ -1,28 +0,0 @@
-package setting
-
-type OAuthInfo struct {
-	ClientId, ClientSecret string
-	Scopes                 []string
-	AuthUrl, TokenUrl      string
-	Enabled                bool
-	EmailAttributeName     string
-	EmailAttributePath     string
-	RoleAttributePath      string
-	RoleAttributeStrict    bool
-	GroupsAttributePath    string
-	AllowedDomains         []string
-	HostedDomain           string
-	ApiUrl                 string
-	AllowSignup            bool
-	Name                   string
-	TlsClientCert          string
-	TlsClientKey           string
-	TlsClientCa            string
-	TlsSkipVerify          bool
-}
-
-type OAuther struct {
-	OAuthInfos map[string]*OAuthInfo
-}
-
-var OAuthService *OAuther