Issue #2107531 by pwolanin, neclimdul, cilefen, dawehner, YesCT, tim.plunkett: Improve DX of local task YAML definitions.

Issue #2135787 by amateescu, Gábor Hojtsy, YesCT: Move static config entity local tasks to local_tasks().yml.

Issue #2102125 by dawehner, tim.plunkett, neclimdul, pwolanin, YesCT, damiankloip, Tim Bozeman: Big Local Task Conversion.

Issue #2095613 by juanolalla, g.oechsler, grisendo | YesCT: Convert all plugin IDs in local_tasks().yml to 'module_name().foo_bar()' naming convention to match routing convention.

Issue #1981368 by tim.plunkett, Crell, webchick: Convert all routes to 'module_name().foo_bar()' naming convention.

Issue #2050919 by neclimdul, pwolanin, damiankloip, dawehner: Replace local task plugin discovery with YamlDiscovery.