Rewrite roadmap plugin to handle multiple projects for a milestone/version

[Cinc-th]

This ticket tracks progress for enhancements to the roadmap plugin to handle multiple projects for milestones or versions. See #12031 for more info.

Part of this rewrite is separation of the version plugin and the two roadmap plugins. Currently one has to have the version plugin activated to use the project enhanced roadmap.

[Cinc-th]

In 14664:

Created skeleton for new roadmap plugin. Refs #12403.

[Cinc-th]

In 14721:

• Allow grouping of milestones by project
• Allow hiding of projects without a milestone

No project filtering at all for now.

Refs #12403.

[Cinc-th]

The following changesets contain additional changes to the roadmap.

In [14992]:

• Some refactoring and PEP0008 changes.
• Removed V0.11 compatibility stuff.
• Preparation for eliminating private roadmap template overriding the Trac default template.

Refs #12031 esp. comment:9

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In [14993]:

• Removed private template for creating roadmap page. Instead the version information is added to the default page.
• Replaced roadmap grouping component by a new one using Genshi template for grouping.
• Allow enabling/disabling of grouping.

Note that filtering by project is currently somewhat broken when grouping by project.

Fixes #10087

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In [14999]:

• New interface to provide data for the roadmap page.
• No more filtering by project in SmpVersionProject. This plugin only adds its data now.
• Component SmpRoadmapProjectFilter rewritten. It does all the filtering for the roadmap in one place now.
• SmpRoadmapModule created for proper calling of data gathering functions in other components.

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In [15000]:

File api.py missing in [14999] added.

Fixes #12556

Refs #12031 esp. comment:9

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In [15001]:

Add project selection control only to roadmap preferences. LEave timeline prefs alone.

Refs #12556

[Cinc-th]

In 15003:

• Settings for SMP on timeline and roadmap pages are remembered again in the session attributes. This was lost in the recent rewrites.
  • Some minor CSS tweaking to make grouping of projects on the roadmap page more visible by adding a slight shadow.

Refs #12403