Improve centos7 osd runner to correctly export fpm and allows dynamic node version switch

[peterzhuamazon]

Description

Improve centos7 osd runner to correctly export fpm and allows dynamic node version switch

1. The fpm utility now correctly exported to env, means OSD core build rpm will not crash anymore
2. Add an entrypoint to dynamically export node version when runner starts. If no params, use 10.24.1; if use -e "NODE_VERSION=14.18.2" it uses 14.18.2. We can add more versions easily later. This makes the dashboards builds the same way as opensearch since you can now apply different node versions for different releases in input manifest.

% docker run --rm -it -u root opensearchstaging/ci-runner:test123
v10.24.1 is already installed.
Now using node v10.24.1 (npm v6.14.12)
Now using node v10.24.1 (npm v6.14.12)

% docker run --rm -it -e "NODE_VERSION=14.18.2" opensearchstaging/ci-runner:test123
v14.18.2 is already installed.
Now using node v14.18.2 (npm v6.14.15)
Now using node v14.18.2 (npm v6.14.15)

Test image: https://hub.docker.com/r/opensearchstaging/ci-runner/tags?page=1&ordering=last_updated&name=ci-runner-centos7-opensearch-dashboards-build-v1

Thanks.

Issues Resolved

#1887

Check List

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[codecov-commenter]

Codecov Report

Merging #1888 (70482e9) into main (a638264) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #1888   +/-   ##
=========================================
  Coverage     94.54%   94.54%           
  Complexity       19       19           
=========================================
  Files           178      178           
  Lines          3630     3630           
  Branches         27       27           
=========================================
  Hits           3432     3432           
  Misses          194      194           
  Partials          4        4           

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[tianleh]

I will test this change in my #1807 once the new tag is ready

[tianleh]

I am performing testing in #1807 by using the new image generated by this PR. I will approve once my test is successful.

[tianleh]

Verified that the new image is working. (sample run)