Optimize codec initialization

[quinchs]

Summary

This PR adds a simple optimization by parallelizing the Execute <=> Initialize phase by "preheating" the codecs to their final form. The more complex (the number of different types and descriptors) a query is(has), the better the performance gain. This also gets gains from long-running queries, as while the binding waits for EdgeDB to return the data, it can preheat codecs.

Small query benchmarks

await client.QueryAsync<string>("select \"Hello, World!\"");

Click to show benchmark results

Before Optimization

|           Method |     Mean |   Error |  StdDev |
|----------------- |---------:|--------:|--------:|
| FullExecuteAsync | 362.6 us | 7.09 us | 5.92 us |

After Optimization

| Method           | Mean     | Error   | StdDev  |
|----------------- |---------:|--------:|--------:|
| FullExecuteAsync | 355.1 us | 6.21 us | 5.51 us |

Larger query benchmarks

public class Person
{
    [EdgeDBProperty("name")]
    public string? Name { get; set; }
    [EdgeDBProperty("email")]
    public string? Email { get; set; }
}
public class Movie
{
    [EdgeDBProperty("title")]
    public string? Title { get; set; }
    [EdgeDBProperty("year")]
    public int Year { get; set; }
    [EdgeDBProperty("director")]
    public Person? Director { get; set; }
    [EdgeDBProperty("actors")]
    public Person[]? Actors { get; set; }
}

await client.QueryAsync<Movie>("select Movie { actors: { email, name }, director: { email, name }, title, year }");

Click to show benchmark results

Before Optimization

|           Method |     Mean |   Error |  StdDev |
|----------------- |---------:|--------:|--------:|
| FullExecuteAsync | 442.3 us | 8.12 us | 7.98 us |

After Optimization

| Method           | Mean     | Error   | StdDev  |
|----------------- |---------:|--------:|--------:|
| FullExecuteAsync | 419.6 us | 8.37 us | 8.96 us |