Use suspense for plotly

[offtherailz]

Description

In order to optimize the bundle size, dynamically loading plotly js lib on demand improves the bundle size of ~1MB of 12 total.

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?

#4297

What is the new behavior?

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

[coveralls]

Coverage decreased (-0.01%) to 81.121% when pulling 2f126be on offtherailz:split_plotlyjs into 6c372a1 on geosolutions-it:master.