Add support for authenticating to azure using Azure Active Directory

This patch adds support for using "azuresql" driver which supports
active directory login.  The change adds a new "protocol" azuresql
which is the driver name for using AD instead of regular SQL Server
authentication.

Author: Fuco1

go.mod

@@ -16,6 +16,9 @@ require (
 )
 
 require (
+	github.com/Azure/azure-sdk-for-go/sdk/azcore v0.19.0 // indirect
+	github.com/Azure/azure-sdk-for-go/sdk/azidentity v0.11.0 // indirect
+	github.com/Azure/azure-sdk-for-go/sdk/internal v0.7.0 // indirect
 	github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 // indirect
 	github.com/Masterminds/goutils v1.1.1 // indirect
 	github.com/Masterminds/semver/v3 v3.1.1 // indirect
@@ -79,6 +82,7 @@ require (
 	github.com/opencontainers/go-digest v1.0.0 // indirect
 	github.com/opencontainers/image-spec v1.0.2 // indirect
 	github.com/opencontainers/runc v1.1.2 // indirect
+	github.com/pkg/browser v0.0.0-20180916011732-0a3d74bf9ce4 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/posener/complete v1.2.3 // indirect
 	github.com/russross/blackfriday v1.6.0 // indirect

go.sum

@@ -1,6 +1,9 @@
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+github.com/Azure/azure-sdk-for-go/sdk/azcore v0.19.0 h1:lhSJz9RMbJcTgxifR1hUNJnn6CNYtbgEDtQV22/9RBA=
 github.com/Azure/azure-sdk-for-go/sdk/azcore v0.19.0/go.mod h1:h6H6c8enJmmocHUbLiiGY6sx7f9i+X3m1CHdd5c6Rdw=
+github.com/Azure/azure-sdk-for-go/sdk/azidentity v0.11.0 h1:OYa9vmRX2XC5GXRAzeggG12sF/z5D9Ahtdm9EJ00WN4=
 github.com/Azure/azure-sdk-for-go/sdk/azidentity v0.11.0/go.mod h1:HcM1YX14R7CJcghJGOYCgdezslRSVzqwLf/q+4Y2r/0=
+github.com/Azure/azure-sdk-for-go/sdk/internal v0.7.0 h1:v9p9TfTbf7AwNb5NYQt7hI41IfPoLFiFkLtb+bmGjT0=
 github.com/Azure/azure-sdk-for-go/sdk/internal v0.7.0/go.mod h1:yqy467j36fJxcRV2TzfVZ1pCb5vxm4BtZPUdYWe/Xo8=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 h1:w+iIsaOQNcT7OZ575w+acHgRric5iCyQh+xv+KJ4HB8=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78/go.mod h1:LmzpDX56iTiv29bbRTIsUNlaFfuhWRQBWjQdVyAevI8=
@@ -310,6 +313,7 @@ github.com/opencontainers/runtime-spec v1.0.3-0.20210326190908-1c3f411f0417/go.m
 github.com/opencontainers/selinux v1.10.0/go.mod h1:2i0OySw99QjzBBQByd1Gr9gSjvuho1lHsJxIJ3gGbJI=
 github.com/ory/dockertest/v3 v3.9.1 h1:v4dkG+dlu76goxMiTT2j8zV7s4oPPEppKT8K8p2f1kY=
 github.com/ory/dockertest/v3 v3.9.1/go.mod h1:42Ir9hmvaAPm0Mgibk6mBPi7SFvTXxEcnztDYOJ//uM=
+github.com/pkg/browser v0.0.0-20180916011732-0a3d74bf9ce4 h1:49lOXmGaUpV9Fz3gd7TFZY106KVlPVa5jcYD1gaQf98=
 github.com/pkg/browser v0.0.0-20180916011732-0a3d74bf9ce4/go.mod h1:4OwLy04Bl9Ef3GJJCoec+30X3LQs/0/m4HFRt/2LUSA=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=

internal/provider/db.go

@@ -9,7 +9,7 @@ import (
 	"time"
 
 	// database drivers
-	_ "github.com/denisenkom/go-mssqldb"
+	_ "github.com/denisenkom/go-mssqldb/azuread"
 	_ "github.com/go-sql-driver/mysql"
 	_ "github.com/jackc/pgx/v4/stdlib"
 
@@ -48,6 +48,9 @@ func (p *provider) connect(dsn string) error {
 		// TODO: also set parseTime=true https://github.com/go-sql-driver/mysql#parsetime
 	case "sqlserver":
 		p.Driver = "sqlserver"
+    case "azuresql":
+		p.Driver = "azuresql"
+		dsn = strings.Replace(dsn, "azuresql://", "sqlserver://", 1)
 	default:
 		return fmt.Errorf("unexpected datasource name scheme: %q", scheme)
 	}
@@ -178,6 +181,8 @@ func (p *provider) typeAndValueForColType(colType *sql.ColumnType) (tftypes.Type
 	kind := scanType.Kind()
 
 	switch p.Driver {
+	case "azuresql":
+		 fallthrough
 	case "sqlserver":
 		switch dbName := colType.DatabaseTypeName(); dbName {
 		case "UNIQUEIDENTIFIER":