Update code coverage tool to use 'Code Coverage Summary' instead of Codecov

[ruokun-niu]

Description

We were using Codecov as code coverage report platform earlier. However, when we erased the history of the repository, Codecov stopped working as it was pointing at an old commit (this commit does not belong to any repository).

I have attempted to configure Codecov to point to the correct commit, but I was not able to do so. After investigating further, seems like the best approach right now is to just ditch Codecov and use an alternative. Specifically, I found a popular tool called 'Code Coverage Summary' and it is much easier to use.

Why we should use Code Coverage Summary:

• Easy to use. We do not need to configure any Github apps. A coverage report is generated on PRs that target the main branch of drasi-core repository, and the report can be viewed in Github Actions (for example https://github.com/drasi-project/drasi-core/actions/runs/11262449528/attempts/1#summary-31318162846)
• No need to configure any sorts of token/secrets. The github action runner will handle everything. This also means that PRs from forked repos has the sufficient permissions to run this
• Has the ability to create coverage report comments in PR (This is not enabled at the moment. Adding this feature means that we need to grant additional permissions to the workflow)
• Has the ability to create/update a coverage badge on our readme page (Not a feature of 'Code Coverage Summary', but can be achieved by using another action like this one https://github.com/marketplace/actions/coverage-badge)
• Easier to ignore parts of the code as we are using tarpaulin (See https://github.com/xd009642/tarpaulin?tab=readme-ov-file#ignoring-code-in-files)

Some tradeoffs from not using Codecov:

• Code coverage summary does not have a dashboard (we still have a pretty good report)
• Difficult to compare the code coverage changes between the current run and the previous ones

Overall, I think this code coverage report tool is just a lot easier to use and maintain and less error prone.

Type of change

• This pull request is a minor refactor, code cleanup, test improvement, or other maintenance task and doesn't change the functionality of Drasi (issue link optional).

Fixes: #issue_number