Fix auth, Bootstrap, Blazor nav, LDAP, and deployment pipeline for working Central UI

Bootstrap served locally with absolute paths and <base href="/">.
LDAP auth uses search-then-bind with service account for GLAuth compatibility.
CookieAuthenticationStateProvider reads HttpContext.User instead of parsing JWT.
Login/logout forms opt out of Blazor enhanced nav (data-enhance="false").
Nav links use absolute paths; seed data includes Design/Deployment group mappings.
DataConnections page loads all connections (not just site-assigned).
Site appsettings configured for Test Plant A; Site registers with Central on startup.
DeploymentService resolves string site identifier for Akka routing.
Instances page gains Create Instance form.

src/ScadaLink.Host/appsettings.Central.json

@@ -26,6 +26,8 @@
       "LdapUseTls": false,
       "AllowInsecureLdap": true,
       "LdapSearchBase": "dc=scadalink,dc=local",
+      "LdapServiceAccountDn": "cn=admin,dc=scadalink,dc=local",
+      "LdapServiceAccountPassword": "password",
       "JwtSigningKey": "scadalink-dev-jwt-signing-key-must-be-at-least-32-characters-long",
       "JwtExpiryMinutes": 15,
       "IdleTimeoutMinutes": 30