[Feature request] Add support for `<ignored text>` to improve the compatibility with Conventional Commits

[wujekbogdan]

The basic Jira Smart Commits syntax is:

<ignored text> <ISSUE_KEY> <ignored text> #<COMMAND> <optional COMMAND_ARGUMENTS>

Conventional Commits syntax is:

<type>[scope]: <description>

In fact both formats are compatible, there are even Comittizen plugins that support that e.g. https://github.com/digitalroute/cz-conventional-changelog-for-jira

It would be great if commitlint-jira also supported this syntax. The only thing that's missing is the support for <ignored text>. The <ignored text> prefix in the Jira format is what <type>[scope]: is in the Conventional Commits format.

Real life example:

feat(api)!: JRA-34 send an email to the customer when a product is shipped

In this case:

• feat(api)!: is <ignored text> in Jira format and <type>[scope]: in the Conventional Commits format
• JRA-34 send an email to the customer when a product is shipped is a <description> in the Conventional Commits format, while in Jira forma it's the <ISSUE_KEY> and <ignored text> in the Jira format.