This commit indtroduces the feature of deploying a Kubernetes deployment
instead of a Daemonset using Filebeat, using a `values.yaml` syntax
as below:

`values.yaml`
---
```yaml
[...]
deploymentType: [daemonset|deployment]
[...]
```

Specifically, this is used for creation of Filebeat instances not
bound to each Worker, conducting non-Worker-related work, such as
collection of AWS CloudTrail logs as described in [1].

[1]:#821

This commit adds a default value test for `deploymentType`.

Additionally,
* `test_deployment_type_deployment`
Checks if a `Deployment` is created but NOT a `DaemonSet`
* `test_deployment_type_daemonset`
Checks if a `DaemonSet` is created but NOT a `Deployment`
* `test_deployment_type_case_insensitive`
Checks if `deploymentType` value is accepted in a case-insensitive way.

This commit uses the MetricBeat Helm chart to create a
Daemonset/Deployment Helm chart for Filebeat.
Uses the
```yaml
daemonset:
  [...]
deployment:
  [...]
```
structure falling back to root key defaults.

The value:
```yaml
serviceAccount: ""
```

was existing twice in the `filebeat/values.yaml` file.

Co-authored-by: Julien Mailleret <8582351+jmlrt@users.noreply.github.com>

Co-authored-by: Julien Mailleret <8582351+jmlrt@users.noreply.github.com>

Co-authored-by: Julien Mailleret <8582351+jmlrt@users.noreply.github.com>