Fix: #11127 Enhance Dockerfile to build image from local source

[brynsofz]

Description

Please check if the PR fulfills these requirements

• The commit message follows our guidelines: https://github.com/geosolutions-it/MapStore2/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x", remove the others)

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

Issue

What is the current behavior?

#11127

What is the new behavior?
Now we have three Dockerfiles:

• Dockerfile – Built manually and tagged as mapstore-base. This image serves as the base for both Dockerfile.root and Dockerfile.custom.
• Dockerfile.root – Builds the image for the root MapStore project. It uses mapstore-base as the base image.
• Dockerfile.custom – Automatically generated in a custom MapStore project as Dockerfile when running createProject.js. It is used to build the custom MapStore image.

Note: Run build.sh before building with either Dockerfile.root or Dockerfile.custom.

Breaking change

Does this PR introduce a breaking change? (check one with "x", remove the other)

• Yes, and I documented them in migration notes
• No

Other useful information