feat: add flag to disable password auth (#5991)

Adds a flag --disable-password-auth that prevents the password login
endpoint from working unless the user has the "owner" (aka. site admin)
role.

Adds a subcommand `coder server create-admin-user` which creates a user
directly in the database with the "owner" role, the "admin" role in
every organization, and password auth. This is to avoid lock-out
situations where all accounts have the login type set to an identity
provider and nobody can login.

cli/configssh_test.go

@@ -532,7 +532,7 @@ func TestConfigSSH_FileWriteAndOptionsFlow(t *testing.T) {
 		{
 			name:    "Start/End out of order",
 			matches: []match{
-				//{match: "Continue?", write: "yes"},
+				// {match: "Continue?", write: "yes"},
 			},
 			writeConfig: writeConfig{
 				ssh: strings.Join([]string{
@@ -547,7 +547,7 @@ func TestConfigSSH_FileWriteAndOptionsFlow(t *testing.T) {
 		{
 			name:    "Multiple sections",
 			matches: []match{
-				//{match: "Continue?", write: "yes"},
+				// {match: "Continue?", write: "yes"},
 			},
 			writeConfig: writeConfig{
 				ssh: strings.Join([]string{