postgresql: Increase timeouts that often fail

According to Sentry, in the last 30 days:

* directory_entry_get_by_path: 958 events, https://sentry.softwareheritage.org/share/issue/c4c2124953a145b2bd325f6f6b7df5a6/
* revision_get: 841 events, https://sentry.softwareheritage.org/share/issue/55fbe01c6f4d4c9bbf684c7608a62ad9/
* release_get: 14 events, https://sentry.softwareheritage.org/share/issue/37c53354541b4c4eaa1faf4e20a68418/
* origin_visit_find_by_date: 114 events, https://sentry.softwareheritage.org/share/issue/a674c12049a941968a717661a0226559/
* origin_get: 79 events, https://sentry.softwareheritage.org/share/issue/bf21d6bc7b24442eb18643d80d936d27/ ; 67 events, https://sentry.softwareheritage.org/share/issue/010a4b1e085a4e2089ba4897c6de6038/