Security Context should be configurable with Cryostat CRD

[ebaron]

With Pod Security Admission, this is fairly important to ensure our workloads can run on a variety of clusters. It doesn't seem like one set of defaults will work for everybody.

At the API level, I expect something like the following:

type CryostatSpec struct {
// ...
	// Options to configure the Security Contexts for the Cryostat application.
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	SecurityOptions *SecurityOptions `json:"securityOptions,omitempty"`
}

type ReportConfiguration struct {
// ...
	// Options to configure the Security Contexts for the Cryostat report generator.
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	SecurityOptions *ReportsSecurityOptions `json:"securityOptions,omitempty"`
}

// SecurityOptions contains Security Context customizations for the
// main Cryostat application at both the pod and container level.
type SecurityOptions struct {
	// Security Context to apply to the Cryostat pod
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	PodSecurityContext *corev1.PodSecurityContext `json:"podSecurityContext,omitempty"`
	// Security Context to apply to the Cryostat application container
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	CoreSecurityContext *corev1.SecurityContext `json:"coreSecurityContext,omitempty"`
	// Security Context to apply to the JFR Data Source container
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	DataSourceSecurityContext *corev1.SecurityContext `json:"dataSourceSecurityContext,omitempty"`
	// Security Context to apply to the Grafana container
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	GrafanaSecurityContext *corev1.SecurityContext `json:"grafanaSecurityContext,omitempty"`
}

// ReportsSecurityOptions contains Security Context customizations for the
// Cryostat report generator at both the pod and container level.
type ReportsSecurityOptions struct {
	// Security Context to apply to the Cryostat report generator pod
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	PodSecurityContext *corev1.PodSecurityContext `json:"podSecurityContext,omitempty"`
	// Security Context to apply to the Cryostat report generator container
	// +optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	ReportsSecurityContext *corev1.SecurityContext `json:"reportsSecurityContext,omitempty"`
}