Add inline chart values

Adds inline chart values, as discussed in gitlab-org/gitlab#372024 (closed)

• Add tests?

Manual testing

I set up an agent with the following configuration:

# .gitlab/agents/test/config.yaml
gitops:
  charts:
    - release_name: test
      source:
        project:
          id: agent-playground/test # the agent config project
          path: chart
      values:
        - inline:
            body: the world is gonna

And a minimal chart with the following default values:

# chart/values.yaml
hello: world
body: once told me

and the following config map template:

# chart/templates/configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ .Values.hello | quote }}
data:
  some: {{ .Values.body | quote }}

Then, in my cluster, the rendered configmap was:

apiVersion: v1
data:
  some: the world is gonna
kind: ConfigMap
metadata:
  annotations:
    meta.helm.sh/release-name: test
    meta.helm.sh/release-namespace: default
  creationTimestamp: "2022-10-28T15:22:41Z"
  labels:
    app.kubernetes.io/managed-by: Helm
  name: world
  namespace: default
  resourceVersion: "1485"
  uid: 8af001df-555e-453b-871c-a72fb47eab20