DOC-2367 restore creating-a-skin.adoc and only remove link to the Skin Tool

[FarzadHayat]

Ticket: DOC-2367

Site: DOC-2367 site

There was an error made in the previous hotfix. The intended change is to just remove the link to the Skin Tool which is only available in TinyMCE 5. Users can still create custom skins in later versions.

Changes:

• DOC-2367 restore creating-a-skin.adoc and only remove link to the Skin Tool

Pre-checks:

• Branch prefixed with feature/7/ or hotfix/7/
• modules/ROOT/nav.adoc has been updated (if applicable)
• Files has been included where required (if applicable)
• [-] Files removed have been deleted, not just excluded from the build (if applicable)
• [-] Files added for New product features, and included a release note entry.

Review:

• Documentation Team Lead has reviewed

[ShiridiGandham]

LGTM