Make pclientd/pcli default_home accessible when using them as librari…

…es (#4729)

## Describe your changes

Changes the location and exposure of the `default_home` functions in
`pcli`/`pclientd` so they can be accessed when used as libraries.

## Checklist before requesting a review

- [x] If this code contains consensus-breaking changes, I have added the
"consensus-breaking" label. Otherwise, I declare my belief that there
are not consensus-breaking changes, for the following reason:

  > minor change to client code organization

crates/bin/pcli/src/lib.rs

@@ -4,6 +4,8 @@
 use {
     crate::{command::*, config::PcliConfig},
     anyhow::Result,
+    camino::Utf8PathBuf,
+    directories::ProjectDirs,
     futures::StreamExt,
     penumbra_proto::{
         box_grpc_svc::BoxGrpcService, custody::v1::custody_service_client::CustodyServiceClient,
@@ -81,3 +83,11 @@ impl App {
         Ok(())
     }
 }
+
+pub fn default_home() -> Utf8PathBuf {
+    let path = ProjectDirs::from("zone", "penumbra", "pcli")
+        .expect("Failed to get platform data dir")
+        .data_dir()
+        .to_path_buf();
+    Utf8PathBuf::from_path_buf(path).expect("Platform default data dir was not UTF-8")
+}

crates/bin/pcli/src/opt.rs

@@ -1,12 +1,12 @@
 use crate::{
     config::{CustodyConfig, GovernanceCustodyConfig, PcliConfig},
+    default_home,
     terminal::ActualTerminal,
     App, Command,
 };
 use anyhow::Result;
 use camino::Utf8PathBuf;
 use clap::Parser;
-use directories::ProjectDirs;
 use penumbra_custody::{null_kms::NullKms, soft_kms::SoftKms};
 use penumbra_proto::box_grpc_svc;
 use penumbra_proto::{
@@ -178,11 +178,3 @@ impl Opt {
         Ok((app, self.cmd))
     }
 }
-
-fn default_home() -> Utf8PathBuf {
-    let path = ProjectDirs::from("zone", "penumbra", "pcli")
-        .expect("Failed to get platform data dir")
-        .data_dir()
-        .to_path_buf();
-    Utf8PathBuf::from_path_buf(path).expect("Platform default data dir was not UTF-8")
-}

crates/bin/pclientd/src/lib.rs

@@ -66,7 +66,7 @@ impl PclientdConfig {
     }
 }
 
-fn default_home() -> Utf8PathBuf {
+pub fn default_home() -> Utf8PathBuf {
     let path = ProjectDirs::from("zone", "penumbra", "pclientd")
         .expect("Failed to get platform data dir")
         .data_dir()