Add maven local by default in order to test local build (especially for Apache Iceberg)

[jbonofre]

No description provided.

[snazy]

mavenLocal() comes with a bunch of drawbacks. In particular it slows down the build and it prevents Gradle from verifying that dependencies come from the "right" source (repository validations don't work).

I'd propose two changes here:

1. Make the addition of mavenLocal() dependent on a system or project property (example here). No need to slow down the build for everyone.
2. Use Gradle included builds - include the Iceberg build into the Polaris build. Then you also get all the benefits of Gradle and can skip the publishing step entirely. It also allows debugging into the Iceberg code.

[jbonofre]

@snazy thanks ! I will update the PR according to your comments.

[jbonofre]

@snazy just to be sure, by "included builds", you mean using --include-build arg right ?

[snazy]

@snazy just to be sure, by "included builds", you mean using --include-build arg right ?

Either this - or in the build scripts - the result's the same