Update ios_mdm_tables.adoc.tmpl

[mmattel]

Description

This update corrects the column widths to have a better rendering result.

Note that the tables can hardly be further optimized because the use of nested tables which are challenging topic and the way the script is designed.

Related Issue

Referencing: owncloud/docs#4480 (Hard to interpret the dashes because of line breaks)
See also the explanation in one of the comments.

Motivation and Context

Improved table rendering

How Has This Been Tested?

Manually mocking a local copy of the resulting adoc file

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• Added changelog files for the fixed issues in folder changelog/unreleased

[mmattel]

@hosy @jesmrec two approvals, I cant merge, can you?