##### SUMMARY
I think the `regex_replace` jinja filter should support `multiline` as the `regex_search` do.
Or maybe use a `flags` parameter to support any `re` flag.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
- `lib/ansible/plugins/filter/core.py`

##### ADDITIONAL INFORMATION
Example: comment a multiline variable.
```yaml
  val: "{{ val | regex_replace('^', '#', multiline=True) }}"
```
str_prefix = ''
    if p['prefix']:
        if p['prefix'] != p['newline']:
            str_prefix = str(
                "%s%s" % (p['prefix'], p['newline'])) * int(p['prefix_count'])
        else:
            str_prefix = str(
                "%s" % (p['newline'])) * int(p['prefix_count'])
    str_text = ("%s%s" % (
        p['decoration'],
        
        text.replace(
            p['newline'], "%s%s" % (p['newline'], p['decoration'])))).replace(
                
                "%s%s" % (p['decoration'], p['newline']),
                "%s%s" % (p['decoration'].rstrip(), p['newline']))
    str_postfix = p['newline'].join(
        [''] + [p['postfix'] for x in range(p['postfix_count'])])
    str_end = ''
    if p['end']:
        str_end = "%s%s" % (p['newline'], p['end'])
    
    return "%s%s%s%s%s" % (
        str_beginning,
        str_prefix,
        str_text,
        str_postfix,
        str_end)
@environmentfilter
def extract(environment, item, container, morekeys=None):