feat: add file-length-limit rule

[alexandear]

This PR adds a new rule file-length-limit.
The rule is inspired on the eslint rule max-length.

This rule has options:

• max (default 0) enforces a maximum number of lines in a file, 0 means the rule is disabled;
• skipBlankLines (default false) if true ignore lines made up purely of whitespace;
• skipComments (default false) if true ignore lines containing just comments.

[ccoVeille]

For record, archives and context

The following linter made by @DanilXO has been merged into golangci-lint

https://github.com/DanilXO/filen

It also was discussed here
golangci/golangci-lint#2881

[DanilXO]

SkipBlankLines is an interesting addition. I'll add it to my linter too. I was thinking about revive as a place to add this, but I liked the idea of ​​golangci-lint with little disabling linters better.

[chavacava]

Thanks @alexandear. I've left some comments. Please also add documentation to the Name method to remove the lint warn.

[chavacava]

IMO the default max must be -1 meaning the rule is not activated. That way we will not pollute the results of those who activate all rules.

[alexandear]

IMO the default max must be -1 meaning the rule is not activated. That way we will not pollute the results of those who activate all rules.

@chavacava Resolved your comments. But I choose 0 in max to disable the rule. This is for consistency with the function-length rule.