[core] Add file format provider SPI

[tchivs]

Purpose

Add an experimental FileFormatProvider SPI so engines can supply ORC/Parquet
format implementations at runtime.

The built-in FileFormatFactory lookup remains the default fallback. Catalog
table-runtime.* options can inject providers without persisting them to table
schemas.

Tests

• mvn -pl paimon-common,paimon-core,paimon-format -am -Pfast-build -DfailIfNoTests=false -Dtest=CoreOptionsTest,FileFormatProviderTest,FormatProviderNoHadoopTest test
• mvn -pl paimon-bundle -am -Pfast-build -DskipTests install
• mvn -pl paimon-api,paimon-common,paimon-core -am -DskipTests spotless:check
• git diff --check apache/master...HEAD
• mvn -N org.apache.rat:apache-rat-plugin:0.15:check

[tchivs]

Could a maintainer rerun UTCase and ITCase Flink 1.x Others / build_test?

All other checks are green. This job failed only in PostgresSyncTableActionITCase.testOptionsChange with a 60s timeout while waiting for the Flink CDC job to reach RUNNING; the same workflow passed on the previous head, and the latest delta only registers the provider option keys in CoreOptions.

I tried gh run rerun 27831245747 --failed, but it requires repository admin rights.