[QA] add tests for new template for WebOffice

[nirajacharya2]

ocis has various template files for OnlyOffice and Collabora.

#11775
#11750

User story: owncloud/ocis#9785

As a user I want to create a document by clicking on a template file so that I can use the templates from a shared folder.

Acceptance Criteria

• click on a template file eg. letter.ott creates a new writable document letter.odt, new document gets opened
• Supported file formats:
• Must:
  • DOTX
  • OTT
• Nice to have:
  • XLTX
  • POTX
  • OTS
  • OTP
• the document gets implicity saved to the users personal space: letter.odt; [Name of template].[corresponding ext]
• filename collisions are implicitly solved: letter (1).odt
• provide the location of letter (1).odt so that clients can show a notification where the file got stored (in personal)

Test cases:

• create file from template
  • create file via context menu
  • create file via sidebar panel
  • create file clicking the template file
  • create multiple files from same template (check suffix)

[nirajacharya2]

test added in #11932