Support multiple postgres hosts

[r65535]

Describe the feature request

I want to use a highly available postgres instance with gatus

Golang's stdlib database/sql doesn't support multiple hostnames to enable failover using the following type of connection string:
postgres://user:password@host1,host2,host3/db?target_session_attrs=primary

Changing the library used for postgres connections to something like github.com/jackc/pgx/v5 would support this feature (and lots of other connection types)

Why do you personally want this feature to be implemented?

Currently I have to manually edit the config file for gatus when the DB fails over

How long have you been using this project?

1 year

Additional information

Happy to PR this change, if it's accepted!