feat: new registration API

[holyspectral]

Description

Today, the scanner registration is done via ScannerRegisterStream and ScannerRegister API. The problem of these two APIs is that, scanner has to extract and send the whole cvedb to controller, and these data will be kept in controller memory until they're handled, even the cvedb is already up-to-date.

The cvedb's raw size has grown from 211.5mb (3.800) to 340.3 MB (4.196) in one year, so this becomes a huge memory pressure when scanner sends the cvedb to the same controller about the same time. If there is a memory limit like 2G in place, when all register requests are sent to the same controller, the controller can be killed immediately by OOM killer.

This PR implements a new gRPC API, ScannerRegisterV3 for scanner to send cvedb metadata first in order to register. If the cvedb is newer, controller will ask the scanner to send the whole cvedb.

Test

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Additional Information

Tradeoff

Potential improvement

[holyspectral]

This is ready for review, but package path in go.mod has to be changed once neuvector side is merged.