refactor: Library improvements + refactoring

[trimox]

• Rename _root to elementRef
• Make directive and component ElementRef public accessible
• Remove directive and component from src/lib file names
• Make event registry listen and unlisten public accessible
• Add passive event handling to event registry
• Prefix private variables with leading underscore
• Functions must specify strongly-typed object(s)
• Add pointerup + mouseup types to ripple's Interaction Handler. reference: Button with ripples stays focused after mouse is moved away material-components/material-components-web#1124 (comment)
• Set default property values
• Rename MDC adapter files to adapter.d.ts
• Refactor MdcFormField
• Prefix events with on instead of handle (e.g.: onKeyPress)
• Set encapsulation to ViewEncapsulation.None
• Refactor mdc-icon-toggle to use mdc-icon
• Change MdcList to Directive

Closes #328

[codecov]

Codecov Report

Merging #329 into master will decrease coverage by 0.68%.
The diff coverage is 93.47%.

@@            Coverage Diff             @@
##           master     #329      +/-   ##
==========================================
- Coverage   91.87%   91.18%   -0.69%     
==========================================
  Files          91       84       -7     
  Lines        4739     4652      -87     
  Branches      910      845      -65     
==========================================
- Hits         4354     4242     -112     
- Misses        385      410      +25

Impacted Files	Coverage Δ
src/lib/cdk/overlay/overlay-ref.ts	75.67% <ø> (ø)	⬆️
src/lib/core/material-icon/material-icon.ts	100% <ø> (ø)
src/lib/drawer/permanent/drawer-permanent.ts	95.91% <100%> (ø)
src/lib/cdk/overlay/overlay-container.ts	100% <100%> (ø)	⬆️
src/lib/core/typography/typography.ts	100% <100%> (ø)
src/lib/card/index.ts	100% <100%> (ø)	⬆️
src/lib/core/ripple/index.ts	100% <100%> (ø)	⬆️
src/lib/core/theme/index.ts	100% <100%> (ø)	⬆️
src/lib/core/elevation/index.ts	100% <100%> (ø)	⬆️
src/lib/linear-progress/linear-progress.ts	100% <100%> (ø)
... and 81 more

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