[IMP] website_blog, website_event: add dynamic snippet carousel

[rusp-odoo]

1. Add dynamic carousel snippet for blog posts Add a new dynamic carousel snippet that displays blog posts in a carousel.

Changes:

• Extract blog filtering logic into BlogPostsMixin.
• Add DynamicSnippetBlogs class extending DynamicSnippetCarousel
• Conditionally show carousel-specific options (slider speed, scrolling mode)

To use: Edit mode -> Blocks -> Blogs -> Select one with "Dynamic Carousel" label

2. Add dynamic carousel snippet for events Add a new dynamic carousel snippet that displays events in a carousel.

Changes:

• Extract event tag filtering logic into EventsMixin.
• Add DynamicSnippetCarouselEvents class extending DynamicSnippetCarousel
• Conditionally show carousel-specific options (slider speed, scrolling mode)

To use: Edit mode -> Blocks -> Events -> Select one with "Dynamic Carousel" label

task-5090459

[robodoo]