Correct accessibility issues with schemas

[glowcloud]

• focus is lost when opening or closing the schema in schemas section

• OpenAPI 2.0/3.0: the information about the property being expanded is narrated only after navigating into […]/information group

accessibility-schema-oas3.mov

• OpenAPI 3.1: keyboard navigation gets trapped in expanded properties, jumps between the property name and collapse all button

accessibility-schema-oas31.mov

• OpenAPI 3.1: focus is not visible for schema name and properties with tab navigation

• OpenAPI 3.1: no name/label for article section

• OpenAPI 2.0/3.0 schema buttons - provide indication which property the button expands/collapses

• OpenAPI 3.1 schema buttons - provide description for expanded/collapsed state

• required property indicated by * - provide label/description required for screen reader users instead of *

This task covers issues originally reported in:

• [Accessibility] WCAG 2.1 1.3.1, and 4.1.2 && Section 508 502.3.1 && Screen Reader Usability #5248
• Swagger UI is not accessible compliant #7350