Implementing multi-stage build workflow

[alaxalves]

Checklist

• I have read the Contribution & Best practices Guide.
• My branch is up-to-date with the upstream master branch.
• The tests pass locally with my changes.
• I have added tests that prove my fix is effective or that my feature works(if appropriate).
• I have added necessary documentation (if appropriate).

Short description of what this resolves/which issues does this fix?:

• I have implemented a better flow to docker builds as recommended here

Changes proposed in this pull request:

• Uses the base image a stage build, thus shortening the img size.

[codecov]

Codecov Report

Merging #2445 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2445   +/-   ##
=======================================
  Coverage   82.62%   82.62%           
=======================================
  Files         146      146           
  Lines        4760     4760           
=======================================
  Hits         3933     3933           
  Misses        827      827

---

Continue to review full report at Codecov.

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[codecov]

Codecov Report

Merging #2445 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2445   +/-   ##
=======================================
  Coverage   82.62%   82.62%           
=======================================
  Files         146      146           
  Lines        4760     4760           
=======================================
  Hits         3933     3933           
  Misses        827      827

---

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 0197ed3...6c23522. Read the comment docs.

[Ana06]

Thanks for the PR @alaxalves! 💐

@hennevogel can you please take a look? 🙏

[Ana06]

@hennevogel ^^