[test infra] auto spec list

***FINALLY***
This change removes [that horrible list of module ids that is always causing conflicts](https://github.com/elasticsearch/kibana/blob/246883577fe92ffbefec2b1aa2c3b68081191d90/test/unit/index.html#L86-L166). We now load every js file in the specs directory, except ones that start with an underscore.

To support this, many filenames needed to change (listed below). In the process of examining everything I found some old/useless test files that I removed and one that was not being run with the previous list. This one file caused the spec count to jump from 819 to 822.

:+1: **added**
specs/filters/label

:x: **deleted**
specs/apps/dashboard/directives/grid.js
specs/apps/dashboard/directives/panel.js
specs/apps/dashboard/index.js
specs/vislib/visualizations/column_chart.js

:arrows_counterclockwise: **renamed**
specs/vislib/visualizations/{_chart.js => chart.js}
specs/vislib/lib/{_error_handler.js => error_handler.js}
specs/vislib/fixture/{vis_fixture.js => _vis_fixture.js}
specs/vislib/fixture/mock_data/series/{data0.js => _data0.js}
specs/vislib/components/tooltip/{render.js => _render.js}
specs/vislib/components/tooltip/{positioning.js => _positioning.js}
specs/utils/routes/{wrap_route_with_prep.js => _wrap_route_with_prep.js}
specs/utils/routes/{work_queue.js => _work_queue.js}
specs/utils/indexed_array/{path_getter.js => _path_getter.js}
specs/utils/indexed_array/{inflector.js => _inflector.js}
specs/plugins/vis_types/vislib/{index.js => _index.js}
specs/index_patterns/{_flatten_search_response.js => flatten_search_response.js}
specs/courier/search_source/{_get_normalized_sort.js => get_normalized_sort.js}
specs/components/index_pattern/{_pattern_to_wildcard.js => pattern_to_wildcard.js}
specs/components/agg_types/utils/{stub_agg_params.js => _stub_agg_params.js}
specs/components/agg_types/bucket_aggs/{histogram.js => _histogram.js}
specs/components/agg_types/bucket_aggs/{date_histogram.js => _date_histogram.js}
specs/components/agg_response/hierarchical/{_transform_aggregation.js => transform_aggregation.js}
specs/components/agg_response/hierarchical/{_extract_buckets.js => extract_buckets.js}
specs/components/agg_response/hierarchical/{_create_raw_data.js => create_raw_data.js}
specs/components/agg_response/hierarchical/{_collect_branch.js => collect_branch.js}
specs/components/agg_response/hierarchical/{_build_hierarchical_data.js => build_hierarchical_data.js}
specs/components/agg_response/hierarchical/{_array_to_linked_list.js => array_to_linked_list.js}