feat: exclude mutations (inProgress)

[bartekleon]

fixes: #1472
closes: #1810

[brodycj]

FYI I think there would be a conflict between the updates in this PR so far and some of the JavaScript mutator improvements in PR #1898. I wonder if we should consider breaking the functionality of JavaScriptMutator.mutate() a little more smartly in PR #1898, or revisit some time later.

[bartekleon]

Well, we can always see later :/

For now, I think we should focus on this PR though since this feature is commonly required by people :/

What's left to do is:

• add an exclusion for a specific mutation in javascript mutator
• add these features to vue mutator

Things which should be done soon:

• improve reporters so these mutations will be called "excluded" or sth like this.

[simondel]

We want to introduce a parser API to support an easy and safe way to make the exclusions. This issue will lay the groundwork for it: #1893. Before this is done, we will not support this option.

We will keep your work here in mind as a reference ♥