feat(tvldb): Import the tvldb/paroxysm source, add a Nix derivation

- This imports the tvldb (actually a thing called 'paroxysm') code
  from https://git.theta.eu.org/eta/paroxysm into the monorepo.
- Additionally, I did a nix thing, yay! \o/
  (well, with tazjin's help)
- 3p/default.nix needed modifying to whitelist pgsql.

Change-Id: Icdf13ca221650dde376f632bd2dd8a087af451bf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/389
Reviewed-by: tazjin <mail@tazj.in>

fun/tvldb/src/models.rs

@@ -0,0 +1,33 @@
+use crate::schema::{entries, keywords};
+use chrono::NaiveDateTime;
+
+#[derive(Queryable)]
+pub struct Keyword {
+    pub id: i32,
+    pub name: String,
+    pub chan: String,
+}
+#[derive(Queryable)]
+pub struct Entry {
+    pub id: i32,
+    pub keyword_id: i32,
+    pub idx: i32,
+    pub text: String,
+    pub creation_ts: NaiveDateTime,
+    pub created_by: String,
+}
+#[derive(Insertable)]
+#[table_name = "keywords"]
+pub struct NewKeyword<'a> {
+    pub name: &'a str,
+    pub chan: &'a str,
+}
+#[derive(Insertable)]
+#[table_name = "entries"]
+pub struct NewEntry<'a> {
+    pub keyword_id: i32,
+    pub idx: i32,
+    pub text: &'a str,
+    pub creation_ts: NaiveDateTime,
+    pub created_by: &'a str,
+}