feat(pindexer): add dex candlestick support to schema (#4894)

## Describe your changes

Closes #4869.

This implementation isn't as fast as it could probably be, but more than
enough to be real time, which is all that really matters.

(Maintaining the summary is annoying and kind of tricky, especially if
you want to correctly handle a "frozen price" for pairs where no
activity is happening)

## 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:

  > indexing only

crates/bin/pindexer/Cargo.toml

@@ -13,6 +13,7 @@ publish = false
 [dependencies]
 anyhow = {workspace = true}
 clap = {workspace = true}
+chrono = {workspace = true}
 cometindex = {workspace = true}
 num-bigint = { version = "0.4" }
 penumbra-shielded-pool = {workspace = true, default-features = false}
@@ -26,6 +27,8 @@ penumbra-governance = {workspace = true, default-features = false}
 penumbra-num = {workspace = true, default-features = false}
 penumbra-asset = {workspace = true, default-features = false}
 penumbra-proto = {workspace = true, default-features = false}
+penumbra-sct = {workspace = true, default-features = false}
+prost = {workspace = true}
 tracing = {workspace = true}
 tokio = {workspace = true, features = ["full"]}
 serde_json = {workspace = true}