Removing Build Scripts for Notifications Plugin

[adityaj1107]

Description

This PR removes the build scripts for the Notifications and the Notifications Dashboard since we have a PR to add them directly to the notifications project (opensearch-project/notifications#398). We are removing them since these take precedence.

Issues Resolved

#1933

Check List

• Commits are signed per the DCO using --signoff

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.

[codecov-commenter]

Codecov Report

Merging #1938 (5bf1549) into main (5e82386) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #1938   +/-   ##
=========================================
  Coverage     94.60%   94.60%           
  Complexity       20       20           
=========================================
  Files           178      178           
  Lines          3633     3633           
  Branches         27       27           
=========================================
  Hits           3437     3437           
  Misses          192      192           
  Partials          4        4           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5e82386...5bf1549. Read the comment docs.

Waiting for other PR to get merged first

[peterzhuamazon]

We will close this PR because due to BE notifications have 2 level2 subfolders within level1 subfolder, the scripts will current sit in build repo.