Expose ledger-subquery version to GQL API

[bryanchriswhite]

Proposal

For now let's add a ReleaseVersion entity and write the version record at boot or something:
- git tag
- git commit hash
- timestamp when deployed

It looks like this is already exposed via the subql framework and we just needed to understand how to use it. TLDR; Apparently we can increment the version property in the package.json of the node and query packages of the subql (git) submodule. (See: #125 (comment) for more.)

• Document subql package.json version update process
• Update package.json versions to present
• Ensure metrics to uses this version

[bryanchriswhite]

It has come to my attention that degrees of freedom already exists for tracking the version of the subquery-node as well as the graphql api services, independently, under the (built-in) _metadata entity:

query {
  _metadata {
    indexerNodeVersion
    queryNodeVersion
  }
}

See subql/packages/query/src/graphql/plugins/GetMetadataPlugin.ts:119 for the complete type definition.

queryNodeVersion

Defined in the subql query package.json as version (see: GetMetadataPlugin.ts:31 & :75)

indexerNodeVersion

Defined in the subql node package.json as version. Returned by the subquery-node's /meta API endpoint (see: subql/packages/node/src/meta/meta.service.ts:44).