Fix some DB issues and lag (#91420)

## About The Pull Request

- ~~The DB schema version define was set to 5.30, the changelog readme
said the latest was 5.28, and the sample insert query in the readme said
it was 5.31~~ (fixed in #91127) Changes the define and readme to 5.32
- Add new entry in readme to rename `character` column in `manifest`
table to `character_name`, because `character` is a reserved word in SQL
and every insert query is failing
- Changed the initial roundstart manifest queries from
number_of_players_readied_up individual insert queries to one mass
insert because I suspect this is add several extra seconds to the start
time

## Why It's Good For The Game
fix yes :)
## Changelog
🆑
server: increment DB schema version to 5.32
server: changed column name in manifest table from character to
character_name because the former is a reserved word
fix: changed round start manifest DB queries from dozens of individual
inserts to one mass insert
fix: hopefully fixed some lag on round start
/🆑

SQL/tgstation_schema_prefixed.sql

@@ -305,7 +305,7 @@ CREATE TABLE `SS13_manifest` (
   `server_port` smallint(5) NOT NULL,
   `round_id` int(11) NOT NULL,
   `ckey` text NOT NULL,
-  `character` text NOT NULL,
+  `character_name` text NOT NULL,
   `job` text NOT NULL,
   `special` text DEFAULT NULL,
   `latejoin` tinyint(1) NOT NULL DEFAULT 0,