Support long database names in PostgreSQL 17.x

[labkey-adam]

Rationale

PostgreSQL used to accept database names longer than 63 characters, truncating them for all operations. As of 17.x, it now fails to connect when the database name is too long. TeamCity uses very long database names, so we now truncate and replace the URL in the DataSource to maintain previous behavior. https://www.labkey.org/home/Developer/issues/issues-details.view?issueId=51676

Also, change getIdentifierMaxLength() to report the database's actual limit. Previously, the dialect reported two or three characters less than the actual limit (we were inconsistent) in an attempt to help callers that might be adding suffixes. Seems like the dialect should just report the facts; callers are now responsible for respecting the database-imposed limit.

[labkey-jeckels]

I'm OK with this change, though it seems wiser to stop generating ones that are so long.

[labkey-adam]

I'm OK with this change, though it seems wiser to stop generating ones that are so long.

@labkey-tchad ?

[labkey-tchad]

I'm OK with this change, though it seems wiser to stop generating ones that are so long.

@labkey-tchad ?

Agreed; it seems bad to just silently truncate to something other than what the configuration specifies. I presume the Postgres folks made the same conclusion.
I can configure TeamCity to override the database name provided by the gradle plugin. It isn't really necessary to use the build ID, that was just something easy and relatively unique.

[labkey-adam]

I'm OK with this change, though it seems wiser to stop generating ones that are so long.

@labkey-tchad ?

Agreed; it seems bad to just silently truncate to something other than what the configuration specifies. I presume the Postgres folks made the same conclusion. I can configure TeamCity to override the database name provided by the gradle plugin. It isn't really necessary to use the build ID, that was just something easy and relatively unique.

I filed an issue with the PostgreSQL team given the long-standing truncation behavior, the now inconsistent behavior (CREATE and ALTER DATABASE work fine, but connecting fails), and the lack of any mention in the release notes... while fully acknowledging that we were relying on undocumented behavior and we can easily work around this. Once TeamCity is using shorter database names I can remove the code that truncates and futzes with the URL in the DataSource. The rest of this PR (having the dialect report the actual max length instead of guessing what callers might do) seems worthwhile, so I'll merge it eventually.

@labkey-tchad The current truncation code should allow us to start testing on PostgreSQL 17.x without adjusting those names. Can you enable PG 17 on this branch?