Make BlazingPizza.Server sample work again

[SteveSandersonMS]

In preparation for all the SSR work we'll be doing, this PR:

• Brings back the benchmarkapps\BlazingPizza.Server perf sample, updating it to run on the framework assemblies built from sources in this repo. Most of the code changes in this PR are just cleaning up and modernizing this, making it use current features like PageTitle, etc.
• Adds a Crank benchmark and instructions Update: After discussion with @sebastienros, the benchmarking aspect is moved to the benchmarks repo. This PR is now simply a matter of fixing what was a broken/outdated sample, with no other changes.

For reference, here are the numbers I just got running it on aspnet-perf-win:

| load                   |         |
| ---------------------- | ------- |
| CPU Usage (%)          | 28      |
| Cores usage (%)        | 332     |
| Working Set (MB)       | 52      |
| Private Memory (MB)    | 144     |
| Start Time (ms)        | 95      |
| First Request (ms)     | 275     |
| Requests               | 539,855 |
| Bad responses          | 0       |
| Latency 50th (ms)      | 6.74    |
| Latency 75th (ms)      | 7.33    |
| Latency 90th (ms)      | 8.90    |
| Latency 95th (ms)      | 9.21    |
| Latency 99th (ms)      | 9.98    |
| Mean latency (ms)      | 7.10    |
| Max latency (ms)       | 59.47   |
| Requests/sec           | 36,073  |
| Requests/sec (max)     | 49,089  |
| Read throughput (MB/s) | 150.34  |

This is before any of the Blazor United-related SSR changes. It's doing server-side prerendering of the Blazing Pizza homepage.