feat(auto-init): initialize components once with multiple mdc.autoInit() calls

[moog16]

fixes #4495

[mdc-web-bot]

All 645 screenshot tests passed for commit f634e82 vs. master! 💯🎉

[mdc-web-bot]

All 645 screenshot tests passed for commit 57bbcef vs. master! 💯🎉

[mdc-web-bot]

All 687 screenshot tests passed for commit 989f298 vs. master! 💯🎉

[moog16]

ready for rereview

[mdc-web-bot]

All 687 screenshot tests passed for commit 165194e vs. master! 💯🎉

[mdc-web-bot]

All 687 screenshot tests passed for commit f20eb17 vs. master! 💯🎉

[abhiomkar]

typo* INITIALIZED_STATE

[mdc-web-bot]

All 687 screenshot tests passed for commit 22a86ae vs. master! 💯🎉

[moog16]

The :not() selector within the mdcAutoInit method is not supported by IE11.

const nodes: Element[] = [].slice.call(root.querySelectorAll(
    `[${AUTO_INIT_ATTR}]:not([${AUTO_INIT_STATE_ATTR}="${INITIALIZED_STATE}"])`));

Looking for other solutions.

Failure seen in https://travis-ci.com/material-components/material-components-web/jobs/200896441

[mdc-web-bot]

All 687 screenshot tests passed for commit 364139d vs. master! 💯🎉

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@63ef3e2). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master    #4691   +/-   ##
=========================================
  Coverage          ?   98.97%           
=========================================
  Files             ?      129           
  Lines             ?     6331           
  Branches          ?      821           
=========================================
  Hits              ?     6266           
  Misses            ?       64           
  Partials          ?        1

Impacted Files	Coverage Δ
packages/mdc-auto-init/index.ts	95.83% <100%> (ø)

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[mdc-web-bot]

All 687 screenshot tests passed for commit 525eb29 vs. master! 💯🎉