Refactored to rename "service terms" to "terms of service" (#9581)

* #124 renamed identififers from service terms to terms of service

* #124 renamed identififers from service terms to terms of service

* 124 renamed ServiceTerms model to TermsOfService

* 124 Renamed EnableCustomServiceTerms feature flag to EnableCustomTermsOfService

* 124 Renamed EnableCustomServiceTerms feature flag to EnableCustomTermsOfService

* #124 fixed formatting

* #124 fixed formatting

* #132 renamed table ServiceTerms to TermsOfService

* #124 renamed some missed files from 'service_terms' to 'terms_of_service'

* #124 removed fixed TODOs

* drop migrate of ServiceTerms table, since backporting

* s/ServiceTerms/TermsOfService/ in tests

* s/AcceptedServiceTermsId/AcceptedTermsOfServiceId/

Change the model attribute, even though the column name will eventually be removed.

* s/accepted_service_terms_id/accepted_terms_of_service_id/ to match redux

* s/serviceTerms/termsOfService

* rename column too, and add max size constraint

* s/EnableCustomServiceTerms/EnableCustomTermsOfService

store/sqlstore/upgrade.go

@@ -502,7 +502,7 @@ func UpgradeDatabaseToVersion54(sqlStore SqlStore) {
 			time.Sleep(time.Second)
 			os.Exit(EXIT_GENERIC_FAILURE)
 		}
-		sqlStore.CreateColumnIfNotExists("Users", "AcceptedServiceTermsId", "varchar(64)", "varchar(64)", "")
+		sqlStore.CreateColumnIfNotExists("Users", "AcceptedTermsOfServiceId", "varchar(64)", "varchar(64)", "")
 		saveSchemaVersion(sqlStore, VERSION_5_4_0)
 	}
 }