##### 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) }}"
```
''' return its argument quoted for shell usage '''
    return shlex_quote(to_text(a))
def fileglob(pathname):
    ''' return list of matched regular files for glob '''
    return [g for g in glob.glob(pathname) if os.path.isfile(g)]
def regex_replace(value='', pattern='', replacement='', ignorecase=False):
    ''' Perform a `re.sub` returning a string '''
    value = to_text(value, errors='surrogate_or_strict', nonstring='simplerepr')
    if ignorecase:
        flags = re.I
    else:
        flags = 0
    _re = re.compile(pattern, flags=flags)
    return _re.sub(replacement, value)
def regex_findall(value, regex, multiline=False, ignorecase=False):
    ''' Perform re.findall and return the list of matches '''
    flags = 0
    if ignorecase:
        flags |= re.I
    if multiline:
        flags |= re.M
    return re.findall(regex, value, flags)
def regex_search(value, regex, *args, **kwargs):