## Issue Addressed
#3766
## Proposed Changes
Adds an endpoint to get the graffiti that will be used for the next block proposal for each validator.
## Usage
```bash
curl -H "Authorization: Bearer api-token" http://localhost:9095/lighthouse/ui/graffiti | jq
```
```json
{
"data": {
"0x81283b7a20e1ca460ebd9bbd77005d557370cabb1f9a44f530c4c4c66230f675f8df8b4c2818851aa7d77a80ca5a4a5e": "mr f was here",
"0xa3a32b0f8b4ddb83f1a0a853d81dd725dfe577d4f4c3db8ece52ce2b026eca84815c1a7e8e92a4de3d755733bf7e4a9b": "mr v was here",
"0x872c61b4a7f8510ec809e5b023f5fdda2105d024c470ddbbeca4bc74e8280af0d178d749853e8f6a841083ac1b4db98f": null
}
}
```
## Additional Info
This will only return graffiti that the validator client knows about.
That is from these 3 sources:
1. Graffiti File
2. validator_definitions.yml
3. The `--graffiti` flag on the VC
If the graffiti is set on the BN, it will not be returned. This may warrant an additional endpoint on the BN side which can be used in the event the endpoint returns `null`.
979b73c9b6