Remove older timeout filter classes

lib/banzai/filter/base_sanitization_filter.rb

lib/banzai/filter/blockquote_fence_legacy_filter.rb

lib/banzai/filter/concerns/timeout_filter_handler.rb

lib/banzai/filter/custom_emoji_filter.rb

lib/banzai/filter/emoji_filter.rb

lib/banzai/filter/external_link_filter.rb

lib/banzai/filter/references/abstract_reference_filter.rb

lib/banzai/filter/syntax_highlight_filter.rb

lib/banzai/filter/timeout_html_pipeline_filter.rb

lib/banzai/filter/timeout_text_pipeline_filter.rb

.../lib/banzai/filter/blockquote_fence_legacy_filter_spec.rb

spec/lib/banzai/filter/external_link_filter_spec.rb

...anzai/filter/references/abstract_reference_filter_spec.rb

spec/lib/banzai/filter/sanitization_filter_spec.rb

spec/lib/banzai/filter/syntax_highlight_filter_spec.rb

spec/lib/banzai/filter/timeout_html_pipeline_filter_spec.rb

spec/lib/banzai/filter/timeout_text_pipeline_filter_spec.rb

...examples/banzai/filters/filter_timeout_shared_examples.rb