Support SSO provider config from infrahub.toml

[ogenstad]

This is an alternate approach to #4739.

The main change is to enforce the same type of settings as we can to with environment variables. So an updated infrahub.toml file would look like this:

[security]

# Just like when using environment variables we require a configured provider
# to be enabled in the config
oauth2_providers = ["provider1", "google"] <- required
oidc_providers = ["provider1", "provider2", "google"] <- required

# only supported names are "provider1", "provider2" and "google"
[security.oauth2_provider_settings.provider1] 
client_id = "your-client-id-1"
client_secret = "your-client-secret-1"
authorization_url = "https://example.com/oauth2/authorize"
token_url = "https://example.com/oauth2/token"
userinfo_url = "https://example.com/oauth2/userinfo"
scopes = ["openid", "profile", "email"]
display_label = "Provider 1"

[security.oauth2_provider_settings.google]
client_id = "your-client-id-2"
client_secret = "your-client-secret-2"

[security.oidc_provider_settings.provider1]
client_id = "your-client-id-1"
client_secret = "your-client-secret-1"
discovery_url = "https://example.com/oicd/discovery"
icon = "mdi:account"
display_label = "Provider 1 (OIDC)"

[security.oidc_provider_settings.provider2]
client_id = "your-client-id-1"
client_secret = "your-client-secret-1"
discovery_url = "https://example.com/oicd/discovery"
icon = "mdi:server"
display_label = "Provider 2 (OIDC)"

[security.oidc_provider_settings.google]
client_id = "your-client-id-1"
client_secret = "your-client-secret-1"

[dgarros]

Would be good to add something to the doc while you're at it

[ogenstad]

Added suggested changes for documentation.