[Feature] Add bookmarks and refer these bookmarks

[SuchiraD]

Description

This is to check the feasibility of adding a custom bookmark and referring/linking it.

In docx, we can create a bookmark for places that we want to refer from somewhere else. Upon clicking the referred link, it will direct us to the bookmark. Following are few technical details.

Bookmark creation

1. Bookmark starts with <w:bookmarkStart w:id="0" w:name="name of the bookmark"/>
2. Bookmarks ends with <w:bookmarkEnd w:id="0"/>
3. The required bookmark item, the <w:r></w:r> section, should be in-between <w:bookmarkStart /> and <w:bookmarkEnd />

<w:p>
    <w:bookmarkStart w:id="id-number" w:name="bookmark name" />
    <w:r>
        <w:t>Text of the bookmark</w:t>
    </w:r>
    <w:bookmarkEnd w:id="id-number" />
</w:p>

Referring bookmark

Bookmark can be linked by <w:hyperlink /> as follows

<w:p>
    <w:hyperlink w:anchor="name of the bookmark">
        <w:r>
            <w:t>Referred link name</w:t>
        </w:r>
    </w:hyperlink>
</w:p>

At the moment, the existing LINK feature in the library is only for external urls. We can extend this to Link bookmarks.

Expected Feature

1. New command/attributes to add bookmarks.

   • +++BOOKMARK ({ name: $name_of_bookmark, label: $label_of_bookmak }) +++ . This can be used to add bookmarks to texts/formatted texts.
   • To add a bookmark to an image, +++IMAGE getImageData($image_url, $width, $height, $bookmark_name) +++. The function should return an additional parameter, bookmarkName. Then we have to place the generated image in-between <w:bookmarkStart /> and <w:bookmarkEnd />
   • To add a bookmark to a link, +++LINK ({url: $link_url, label: $label_of_link, bookmarkName: $name_of_bookmark}) +++

2. Extend Link to refer bookmarks
   eg: +++LINK ({label: $label_of_link, bookmarkLink: $name_of_bookmark}) +++

p.s. Referred reported issue - #257 (comment)