Add API endpoint for getting all pull requests related to a user (BB-14638)

Would it be possible to add an api call that allows the retrieval of all pull requests that concern a given user.

Eg.

GET https://api.bitbucket.org/2.0/repositories/

{owner}

/

{repo_slug}

/pullrequests?state=[OPEN, MERGED, DECLINED]*&user=

{concerninguser}

&useris=[REVIEWER,AUTHOR]*