chore(viz): rename v1 and v2 charts

[villebro]

SUMMARY

This makes the "v2" charts the "official ones" by removing the version suffix, and add "(legacy)" to the old ones that they're replacing.

AFTER

Now the viz switcher doesn't feature the v2 name (here I'm using generic x-axis):

BEFORE

Currently many charts feature a "v2" suffix:

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #22369 (ad5016d) into master (3a442e0) will not change coverage.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master   #22369   +/-   ##
=======================================
  Coverage   66.86%   66.86%           
=======================================
  Files        1847     1847           
  Lines       70562    70562           
  Branches     7742     7742           
=======================================
  Hits        47179    47179           
  Misses      21382    21382           
  Partials     2001     2001           

Flag	Coverage Δ
javascript	53.82% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ugins/legacy-plugin-chart-pivot-table/src/index.js	66.66% <ø> (ø)
...d/plugins/legacy-plugin-chart-treemap/src/index.js	66.66% <ø> (ø)
...plugins/legacy-preset-chart-nvd3/src/Area/index.js	66.66% <ø> (ø)
.../plugins/legacy-preset-chart-nvd3/src/Bar/index.js	66.66% <ø> (ø)
...plugins/legacy-preset-chart-nvd3/src/Line/index.js	66.66% <ø> (ø)
.../plugin-chart-echarts/src/Timeseries/Area/index.ts	33.33% <ø> (ø)
...-chart-echarts/src/Timeseries/Regular/Bar/index.ts	33.33% <0.00%> (ø)
...chart-echarts/src/Timeseries/Regular/Line/index.ts	33.33% <ø> (ø)
.../plugins/plugin-chart-echarts/src/Treemap/index.ts	50.00% <ø> (ø)
...ugins/plugin-chart-pivot-table/src/plugin/index.ts	66.66% <ø> (ø)

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[rusackas]

LGTM! Thanks for the good housekeeping!

[geido]

Looks good!

[michael-s-molina]

@rusackas This PR will probably require an update to Preset docs as the v2 suffix is referenced on some pages and there's no legacy suffix currently.