[Developer] Add more prominent notice to GitHub issue template to direct bug reports to JIRA

[asfimport]

Many people are deleting the issue template without reading it. I will change the template to feature a more prominent notice about filing bug reports in JIRA

Recent examples

• Consider shading the flatbuffers dependency (java) #4489
• Field Metadata Not Read #4495

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

PRs and other links:

• GitHub Pull Request #4536

_{Note: This issue was originally created as ARROW-5526. Please see the migration documentation for further details.}

[asfimport]

Neal Richardson / @nealrichardson:
Alternatively, we could turn off GitHub issues. Just spot checking some of the big Apache projects that come to mind (Spark, Hadoop, etc.), none of them have issues enabled.

[asfimport]

Wes McKinney / @wesm:
In our experience prior to enabling GitHub issues, many would-be bug reporters would simply not bother reporting at all. So I'd rather capture the issue if the contributor does not take the time to read the project README

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 4536
#4536