Feat: Add `--builder-boost-factor` parameter to the VC

[yorickdowne]

A home validator with limited bandwidth may prefer to always use builder blocks, because a local block would be orphaned when blobs can't be uploaded in time, post-Fusaka.

Teku can currently configure this on the CL, but not the VC. Request: Add such a flag on the VC. It could mirror the --builder-bid-compare-factor and become say --validator-builder-bid-compare-factor.

The flags I've seen on other clients, e.g. Lighthouse, are --builder-boost-factor <factor>, where <factor> is an integer and can go up to 2**64 - 1, and --prefer-builder-proposals, which is a user-friendly alias for a high builder boost factor. This is on the VC. My understanding is this then instructs the CL on the preference it should use.

[tbenr]

Thanks for reminding us about this. We will keep this in our backlog