feat: email validator and a string formatter

[arjunlalb]

Description

Validator for email.
String formatter to split a comma separated list into a string array.

Testing

UTs added.

Checklist:

• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

Merging #656 (db6d916) into main (5d93503) will increase coverage by 6.11%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #656      +/-   ##
==========================================
+ Coverage   79.12%   85.23%   +6.11%     
==========================================
  Files         778      779       +1     
  Lines       16030    16040      +10     
  Branches     2068     2068              
==========================================
+ Hits        12684    13672     +988     
+ Misses       3312     2333     -979     
- Partials       34       35       +1     

Impacted Files	Coverage Δ
projects/common/src/public-api.ts	100.00% <100.00%> (ø)
...rc/utilities/formatters/string/string-formatter.ts	97.14% <100.00%> (+0.36%)	⬆️
...common/src/utilities/validators/email-validator.ts	100.00% <100.00%> (ø)
.../selections/observability-specification-builder.ts	64.21% <0.00%> (+2.10%)	⬆️
projects/components/src/popover/popover-ref.ts	93.54% <0.00%> (+3.22%)	⬆️
...nents/utils/d3/d3-visualization-builder.service.ts	82.38% <0.00%> (+3.77%)	⬆️
...ects/common/src/utilities/coercers/date-coercer.ts	100.00% <0.00%> (+4.34%)	⬆️
...load-async/wrapper/load-async-wrapper.component.ts	100.00% <0.00%> (+4.54%)	⬆️
projects/common/src/time/time-range.service.ts	80.64% <0.00%> (+6.45%)	⬆️
... and 75 more

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[github-actions]

Unit Test Results

    4 files  ±0  243 suites  +1   14m 58s ⏱️ +20s
872 tests +3  872 ✔️ +3  0 💤 ±0  0 ❌ ±0 
876 runs  +3  876 ✔️ +3  0 💤 ±0  0 ❌ ±0 

Results for commit 085462b. ± Comparison against base commit 5d93503.

[anandtiwary]

We can also look into https://github.com/ngneat/forms-manager . @arjunlalb Could you please check if it can simplify your use case?