Document or automate the artifacts creation process

Related to #16062.

Despite there being many more tags listed in the SCR:

```
cat validation/standard/standard-versions-mainnet.toml | grep op-contracts/
["op-contracts/v4.0.0-rc.6"]
["op-contracts/v3.0.0"]
["op-contracts/v3.0.0-rc.2"]
["op-contracts/v3.0.0-rc.1"]
["op-contracts/v2.0.0"]
["op-contracts/v2.0.0-rc.1"]
["op-contracts/v1.8.0"]
["op-contracts/v1.8.0-rc.4"]
["op-contracts/v1.6.0"]
["op-contracts/v1.4.0"]
["op-contracts/v1.3.0"]
```

The only valid tags according to `op-deployer bootstrap` are:

```
./bin/op-deployer bootstrap implementations --artifacts-locator tag://op-contracts/v4.0.0-rc.6
Application failed: failed to populate config: failed to set field ArtifactsLocator: unsupported tag: op-contracts/v4.0.0-rc.6
Valid tags are:
op-contracts/v1.6.0
op-contracts/v1.7.0-beta.1+l2-contracts
op-contracts/v1.8.0-rc.4
op-contracts/v2.0.0-rc.1
op-contracts/v3.0.0-rc.2
```

The process for adding new artifacts should be documented, and ideally automated, such that they are created whenever a new tag is created.

Start with validation/standard/standard-versions-mainnet.toml and the bin/op-deployer bootstrap implementations entry point to trace how artifact tags are validated and created. Compare the tags listed in the standard versions file with the valid tags reported by the command. Done means the artifact-creation process is documented or automated so newly created tags become valid bootstrap artifacts.

Written by the indexing model from the issue text.