Allow more expressions for selected statements

[dey4ss]

As raised in #213 and discussed in #215, some valid expressions, such as negative numbers, are not supported by the INSERT statement. Thus, this PR carefully extends the range of expressions allowed in the INSERT statements, but also in EXECUTE statements and in hints.

I looked into SQL:2023 to see which expressions are allowed inside the VALUES list of an INSERT statement, and there are a lot of valid alternatives in the standard. Some of them are collected in the following:

-| <scalar subquery>
-| <case expression>
+| <cast specification>
 | <boolean value expression>
 | <numeric value expression>
 | <string value expression>
 | <datetime value expression>
 | <interval value expression>
-| <user-defined type value expression>
-| <reference value expression>
-| <collection value expression>
-| <JSON value expression>

Note that all of this is scattered accross many pages and places as part of complex hierarchies. I collected just a few possibilities here. I marked newly supported (+) and some unsupported (-) alternatives. Furthermore, this PR also allows for signed numerical/interval expressions (a.k.a unary minus of numeric/interval). Cast expressions are restricted to only take other allowed expressions as input.

Besides, this PR updates the CI runners to Ubuntu 24.04 and uses its shipped clang/gcc versions. While checking the runners, I noticed that (i) there was an issue with the member variable introduced in #240 and (ii) that did not cause the CI to fail. I sneaked in fixes for both.

fixes #215

[sandrain]

Looking forward to seeing this patch land. 👍

[Bouncner]

LGTM.