Add custom headers

[bpackter]

Overview

SNOW-Add custom headers

Pre-review self checklist

• PR branch is updated with all the changes from master branch
• The code is correctly formatted (run mvn -P check-style validate)
• New public API is not unnecessary exposed (run mvn verify and inspect target/japicmp/japicmp.html)
• The pull request name is prefixed with SNOW-XXXX:
• Code is in compliance with internal logging requirements

External contributors - please answer these questions before submitting a pull request. Thanks!

1. What GitHub issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Issue: #2015

2. Fill out the following pre-review checklist:

   • I am adding a new automated test(s) to verify correctness of my new code
   • I am adding new logging messages
   • I am modifying authorization mechanisms
   • I am adding new credentials
   • I am modifying OCSP code
   • I am adding a new dependency or upgrading an existing one
   • I am adding new public/protected component not marked with @SnowflakeJdbcInternalApi (note that public/protected methods/fields in classes marked with this annotation are already internal)

3. Please describe how your code solves the related issue.

There is no options to add custom headers on each snowflake request (login, query, telemetry, heartbeat etc..)
This is needed in our case because we are calling snowflake from proxy and proxy enforce us to add jwt in some custom header.

This change
add an option to add map of custom headers in session coonig.
make sure headers are added on each request

[github-actions]

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