This commit lays the foundation for displaying coverage results
from `bazel coverage`.

For the time being, the functionality is only exposed through the
user-defined tasks in the `tasks.json`. It is thereby a bit hard to
discover. But this is fine for the time being, because coverage still
has a couple of rough edges anyway. As soon as it is more stable, we
should add builtin commands and expose coverage runs also in the "Bazel
Build Target" tree.

Changes in this commit:
* Bumps the VS Code version to 1.88, i.e. the first VS Code version
  which supports the test coverage API.
* Upgrades to ES2022.  I wanted to use `replaceAll` which was introduced
  in ES2021.
  VS Code 1.88 is based on Node 18 which in turn is based on V8 10.1. V8
  10.18 supports ECMA-262 also known as ES2023.  However, ES2023 is not
  yet available a target language in the `tsconfig.json`.  Furthermore,
  Firefox does not fully support ES2023, yet. While web browsers are
  currently not relevant, they might become so in the future if we want
  to turn this into a browser-enabled VSCode extension.
  An upgrade to ES2021 would have been sufficient, but I went directly
  to ES2022 because it might some of the other new features might also
  turn out useful.
* Introduces a custom LCOV parser. I could not find any other
  high-quality open-source parser. E.g., most other parser don't
  properly parse function names with `:` and / or `,` in them.
* Introduces test cases for that custom LCOV parser.

Future work:
* Support for branch coverage
* Demangling of function names
* Builtin commands to trigger coverage runs & offer them in the "Bazel
  Build Tree"

Tested with: Java, C++, Go, Rust
Untested: Python, Swift, Kotlin, Scala and many more

This is the first step towards bazel-contrib#362

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