feat(chart/opensearch): add ability for serviceMonitor basicauth

[eyenx]

Description

Right now there is non possibility to set a basicAuth configuration for the serviceMonitor. This PR adds it

Check List

• [x] Commits are signed per the DCO using --signoff

For any changes to files within Helm chart directories:

• [x] Helm chart version bumped
• [x] Helm chart CHANGELOG.md updated to reflect change

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[peterzhuamazon]

Note: We are in the review of an older PR now so will come back to this a little later.