[SPARK-35969][K8S] Make the pod prefix more readable and tallied with K8S DNS Label Names

[yaooqinn]

What changes were proposed in this pull request?

By default, the executor pod prefix is generated by the app name. It handles characters that match [^a-z0-9\\-] differently. The '.' and all whitespaces will be converted to '-', but other ones to empty string. Especially,  characters like '_', '|' are commonly used as a word separator in many languages.

According to the K8S DNS Label Names, see https://kubernetes.io/docs/concepts/overview/working-with-objects/names/#dns-label-names, we can convert all special characters to -.

 
For example,

scala> "xyz_abc_i_am_a_app_name_w/_some_abbrs".replaceAll("[^a-z0-9\\-]", "-").replaceAll("-+", "-")
res11: String = xyz-abc-i-am-a-app-name-w-some-abbrs

scala> "xyz_abc_i_am_a_app_name_w/_some_abbrs".replaceAll("\\s+", "-").replaceAll("\\.", "-").replaceAll("[^a-z0-9\\-]", "").replaceAll("-+", "-")
res12: String = xyzabciamaappnamewsomeabbrs

scala> "time.is%the￥most$valuable_——————thing,it's about time.".replaceAll("[^a-z0-9\\-]", "-").replaceAll("-+", "-")
res9: String = time-is-the-most-valuable-thing-it-s-about-time-

scala> "time.is%the￥most$valuable_——————thing,it's about time.".replaceAll("\\s+", "-").replaceAll("\\.", "-").replaceAll("[^a-z0-9\\-]", "").replaceAll("-+", "-")
res10: String = time-isthemostvaluablethingits-about-time-

Why are the changes needed?

For better UX

Does this PR introduce any user-facing change?

yes, the executor pod name might look better

How was this patch tested?

add new ones

[SparkQA]

Test build #140504 has finished for PR 33171 at commit 9c33988.

• This patch fails to build.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #140509 has finished for PR 33171 at commit ac79194.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/45016/

[yaooqinn]

cc @dongjoon-hyun @holdenk thanks

[SparkQA]

Kubernetes integration test status success
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/45016/

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/45022/

[SparkQA]

Kubernetes integration test status success
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/45022/

[dongjoon-hyun]

+1, LGTM. Thank you, @yaooqinn .
Merged to master for Apache Spark 3.2.0.