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>

internal/command/instance_idp.go

@@ -1763,6 +1763,8 @@ func (c *Commands) prepareAddInstanceSAMLProvider(a *instance.Aggregate, writeMo
 					cert,
 					provider.Binding,
 					provider.WithSignedRequest,
+					provider.NameIDFormat,
+					provider.TransientMappingAttributeName,
 					provider.IDPOptions,
 				),
 			}, nil
@@ -1811,6 +1813,8 @@ func (c *Commands) prepareUpdateInstanceSAMLProvider(a *instance.Aggregate, writ
 				c.idpConfigEncryption,
 				provider.Binding,
 				provider.WithSignedRequest,
+				provider.NameIDFormat,
+				provider.TransientMappingAttributeName,
 				provider.IDPOptions,
 			)
 			if err != nil || event == nil {
@@ -1854,6 +1858,8 @@ func (c *Commands) prepareRegenerateInstanceSAMLProviderCertificate(a *instance.
 				c.idpConfigEncryption,
 				writeModel.Binding,
 				writeModel.WithSignedRequest,
+				writeModel.NameIDFormat,
+				writeModel.TransientMappingAttributeName,
 				writeModel.Options,
 			)
 			if err != nil || event == nil {