[website_docs] Fix page meta links and rename file

[chalin]

• Contributes "View page source" and "Edit this page" button broken opentelemetry.io#1096
• Contributes to [CI/infra] Doc file names: use kebab-case not snake_case opentelemetry.io#780

/cc @cartermp @austinlparker

[codecov]

Codecov Report

Merging #578 (5f7c8a1) into main (09cecbe) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main     #578   +/-   ##
=========================================
  Coverage     82.66%   82.66%           
  Complexity     1047     1047           
=========================================
  Files           115      115           
  Lines          2660     2660           
=========================================
  Hits           2199     2199           
  Misses          461      461           

Flag	Coverage Δ
7.4	82.83% <ø> (ø)
8.0	82.66% <ø> (ø)
8.1	82.84% <ø> (ø)

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[chalin]

Thanks for the approval and merge @brettmc.