Misconfigured model leads to broken database api

[dbeuchler]

Describe the bug
After a misconfigured database model, the UI stays in "Loading...".

To Reproduce
Steps to reproduce the behavior:

1. Go to CommandCenter
2. Click on a model
3. Change connector to postgresql
4. Enter connection string "something-weired"
5. Save

Response of the getDatabases() call:

{
    "title": "500 - Internal Server Error",
    "exception": "System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0.\n   at System.Data.Common.DbConnectionOptions.GetKeyValuePair(String connectionString, Int32 currentPosition, StringBuilder buffer, Boolean useOdbcRules, String& keyname, String& keyvalue)\n   at System.Data.Common.DbConnectionOptions.ParseInternal(Dictionary`2 parsetable, String connectionString, Boolean buildChain, Dictionary`2 synonyms, Boolean firstKey)\n   at System.Data.Common.DbConnectionOptions..ctor(String connectionString, Dictionary`2 synonyms, Boolean useOdbcRules)\n   at System.Data.Common.DbConnectionStringBuilder.set_ConnectionString(String value)\n   at Npgsql.NpgsqlConnectionStringBuilder..ctor(String connectionString)\n   at Moryx.Model.PostgreSQL.NpgsqlModelConfigurator.CreateConnectionStringBuilder(IDatabaseConfig config, Boolean includeModel)\n   at Moryx.Model.PostgreSQL.NpgsqlModelConfigurator.BuildConnectionString(IDatabaseConfig config, Boolean includeModel)\n   at 
[...]
}

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots

Environment:

• Hardware:
• OS: alpine-linux docker host dotnet/aspnet:6.0-alpine
• Version 6.3.2

Additional context
Add any other context about the problem here.