chore(styling): initiate styling (SASS) setup within the SDK

[arnautov-anton]

🎯 Goal

Prepare styling environment within SDK.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.04%. Comparing base (d2d41b6) to head (e9a1039).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2906      +/-   ##
==========================================
- Coverage   80.07%   80.04%   -0.04%     
==========================================
  Files         506      506              
  Lines       10777    10777              
  Branches     2709     2709              
==========================================
- Hits         8630     8626       -4     
- Misses       1894     1898       +4     
  Partials      253      253              

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[arnautov-anton]

Basing these efforts on normalized styling so that styling across browsers is "smoother".

[github-actions]

Size Change: +104 B (+0.04%)

Total Size: 284 kB

Filename	Size	Change
./dist/css/index.css	104 B	+104 B (new file)	🆕

ℹ️ View Unchanged

Filename	Size
./dist/audioProcessing-BbOs2wMd.js	1.32 kB
./dist/Channel-pqo4jV1s.js	24.4 kB
./dist/ChannelPreview-BNyNO58P.js	17.8 kB
./dist/cjs/emojis.js	3.29 kB
./dist/cjs/experimental.js	5.8 kB
./dist/cjs/index.js	165 kB
./dist/cjs/mp3-encoder.js	1.27 kB
./dist/css/v2/emoji-mart.css	1.84 kB
./dist/css/v2/emoji-replacement.css	300 B
./dist/css/v2/index.css	39.4 kB
./dist/css/v2/index.layout.css	22.8 kB
./dist/MessageInputContext-Buw2XInb.js	314 B

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