Add make command to run a specific e2e test

[swang392]

What does this PR do?

Adds a new make command to run a specific E2E test by setting the E2E_RUN_REGEX environment variable in your terminal to the name of the desired test.
Removes parentheses from E2E test names

Motivation

Sometimes we don't want to run the entire E2E test suite, especially when trying to check or develop one test.

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

• set E2E_RUN_REGEX in your terminal window to the full name of an E2E test. ex: export E2E_RUN_REGEX=TestLocalKindSuite/TestGenericK8s/Minimal_DDA_config
• run make e2e-tests
• check that only the test you specified has run. You should see a line printing out the value of E2E_RUN_REGEX in the output.
• remove the variable you set for E2E_RUN_REGEX -- export E2E_RUN_REGEX=
• run make e2e-tests
• check that all of the e2e tests run

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 48.94%. Comparing base (a408715) to head (f235750).

Additional details and impacted files

@@                   Coverage Diff                    @@
##           fanny/refactor-kind-e2e    #1547   +/-   ##
========================================================
  Coverage                    48.94%   48.94%           
========================================================
  Files                          227      227           
  Lines                        20636    20636           
========================================================
  Hits                         10101    10101           
  Misses                       10010    10010           
  Partials                       525      525           

Flag	Coverage Δ
unittests	48.94% <ø> (ø)

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