Extract pd auto-https code into standalone utility crate, or else make it unnecessary

[hdevalence]

Is your feature request related to a problem? Please describe.

In #1406, we added automatic HTTPS support to pd. However, this is only usable inside of pd, but there are other places we would like to have HTTPS support, including:

• pclientd (cf Transport security and client authentication for View and Custody services #1556)
• the ceremony coordinator (Tracking Issue: decentralized setup to generate proving and verification keys for mainnet #712)

Doing this involved writing custom wrappers between Tokio types and types used by the rustls_acme crate we use for auto-HTTPS.

Also, the code in pd has some special tweaks that turned out to be necessary to get things working and were difficult to debug. For instance, we had mysterious issues with grpc-web support until we realized that we needed to manually configure TLS ALPN settings. Ideally these tweaks could be shared with other code, but on the other hand, the work of figuring them out might be the more important part.

Describe the solution you'd like

There are two paths forward, depending on whether or not we can discard our wrapper code.

In the first path, we would make the custom shim code unnecessary. Newer versions of rustls_acme apparently have Tokio support. We could attempt to remove our wrapper code. Then we could just copy over the setup code from pd into other binaries we want to have auto-https.

In the second path, if we still needed the custom shim code, we should extract it into a new crate under crates/util, maybe crates/util/penumbra-auto-https. Then other crates in our workspace could depend on it.