feat(web): Add session handling implementation

[martinkuba]

Which problem is this PR solving?

Follow up to #4972

Discussed in issue open-telemetry/opentelemetry-js-contrib#2358

Short description of the changes

This adds an implementation of session management for web. It introduces a SessionManager class that is responsible for starting, ending, and persisting sessions.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• unit tests
• example added to examples/opentelemetry-web

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.25%. Comparing base (1370810) to head (58005d4).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5173      +/-   ##
==========================================
+ Coverage   93.19%   93.25%   +0.06%     
==========================================
  Files         314      315       +1     
  Lines        8077     8144      +67     
  Branches     1622     1636      +14     
==========================================
+ Hits         7527     7595      +68     
+ Misses        550      549       -1     

Files with missing lines	Coverage Δ
...rimental/packages/web-common/src/SessionManager.ts	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests
• JS Bundle Analysis - Avoid shipping oversized bundles