feat(saml): allow setting nameid-format and alternative mapping for transient format (#7979)

# Which Problems Are Solved

ZITADEL currently always uses
`urn:oasis:names:tc:SAML:2.0:nameid-format:persistent` in SAML requests,
relying on the IdP to respect that flag and always return a peristent
nameid in order to be able to map the external user with an existing
user (idp link) in ZITADEL.
In case the IdP however returns a
`urn:oasis:names:tc:SAML:2.0:nameid-format:transient` (transient)
nameid, the attribute will differ between each request and it will not
be possible to match existing users.

# How the Problems Are Solved

This PR adds the following two options on SAML IdP:
- **nameIDFormat**: allows to set the nameid-format used in the SAML
Request
- **transientMappingAttributeName**: allows to set an attribute name,
which will be used instead of the nameid itself in case the returned
nameid-format is transient

# Additional Changes

To reduce impact on current installations, the `idp_templates6_saml`
table is altered with the two added columns by a setup job. New
installations will automatically get the table with the two columns
directly.
All idp unit tests are updated to use `expectEventstore` instead of the
deprecated `eventstoreExpect`.

# Additional Context

Closes #7483
Closes #7743

---------

Co-authored-by: peintnermax <max@caos.ch>
Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>

cmd/setup/setup.go

@@ -139,6 +139,7 @@ func Setup(config *Config, steps *Steps, masterKey string) {
 	steps.s24AddActorToAuthTokens = &AddActorToAuthTokens{dbClient: queryDBClient}
 	steps.s25User11AddLowerFieldsToVerifiedEmail = &User11AddLowerFieldsToVerifiedEmail{dbClient: esPusherDBClient}
 	steps.s26AuthUsers3 = &AuthUsers3{dbClient: esPusherDBClient}
+	steps.s27IDPTemplate6SAMLNameIDFormat = &IDPTemplate6SAMLNameIDFormat{dbClient: esPusherDBClient}
 
 	err = projection.Create(ctx, projectionDBClient, eventstoreClient, config.Projections, nil, nil, nil)
 	logging.OnError(err).Fatal("unable to start projections")
@@ -190,6 +191,7 @@ func Setup(config *Config, steps *Steps, masterKey string) {
 		steps.s18AddLowerFieldsToLoginNames,
 		steps.s21AddBlockFieldToLimits,
 		steps.s25User11AddLowerFieldsToVerifiedEmail,
+		steps.s27IDPTemplate6SAMLNameIDFormat,
 	} {
 		mustExecuteMigration(ctx, eventstoreClient, step, "migration failed")
 	}