Add CLI options to run metrics endpoint over HTTPS

[ConnorJC3]

Is this a bug fix or adding new feature?

New feature (and related bugfix)

What is this PR about? / Why do we need it?

Add options to run metrics endpoint over HTTPS

Adds the ability to run the metrics server via HTTPS by supplying a certificate and key.

Validate options in main.go

Adds missing Validate() call to main.go

What testing is done?

CI/manual/Added unit tests

$ AWS_REGION="us-west-2" ./bin/aws-ebs-csi-driver controller --http-endpoint=":6443" --metrics-cert-file=`pwd`/server.crt --metrics-key-file=`pwd`/server.key 
I0419 18:04:46.442557   29484 metrics.go:96] "Metric server listening" address=":6443" path="/metrics"
I0419 18:04:46.444976   29484 driver.go:68] "Driver Information" Driver="ebs.csi.aws.com" Version="v1.29.1"

$ curl -kv https://localhost:6443
*   Trying 127.0.0.1:6443...
* Connected to localhost (127.0.0.1) port 6443
* ALPN: curl offers h2,http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN: server accepted h2
* Server certificate:
*  subject: C=XX; L=Default City; O=Default Company Ltd
*  start date: Apr 19 18:02:41 2024 GMT
*  expire date: Apr 17 18:02:41 2034 GMT
*  issuer: C=XX; L=Default City; O=Default Company Ltd
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
* using HTTP/2
* [HTTP/2] [1] OPENED stream for https://localhost:6443/
* [HTTP/2] [1] [:method: GET]
* [HTTP/2] [1] [:scheme: https]
* [HTTP/2] [1] [:authority: localhost:6443]
* [HTTP/2] [1] [:path: /]
* [HTTP/2] [1] [user-agent: curl/8.3.0]
* [HTTP/2] [1] [accept: */*]
> GET / HTTP/2
> Host: localhost:6443
> User-Agent: curl/8.3.0
> Accept: */*
> 
< HTTP/2 404 
< content-type: text/plain; charset=utf-8
< x-content-type-options: nosniff
< content-length: 19
< date: Fri, 19 Apr 2024 18:05:05 GMT
< 
404 page not found

[github-actions]

Code Coverage Diff

File	Old Coverage	New Coverage	Delta
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/metrics/metrics.go	72.0%	66.7%	-5.3

[AndrewSirenko]

Code itself lgtm other than missing options documentation page updates

Thank you for removing the 2 panics.

[torredil]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: torredil

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[ConnorJC3]

/retest