Tests/BundleTest: Drop use of ChangeLog.txt

The test just wants a source file from outside its tree.
Use README.rst instead.
Remove ChangeLog.txt

This file has not been maintained since the conversion from CVS
to Git.  It provides not useful information in modern releases.
Remove ChangeLog.manual

This file was used during the 2.8 release series to hold notes generated
from 'git shortlog'.  In CMake 3.0 it is replaced by Help/release/*.rst
documents containing more useful manually written release notes.
Help: Add hyperlink targets for argument types in cmake-language(7)

Add reStructuredText hyperlink targets for the bracket, quoted, and
unquoted argument sections.
Help: Add CMake 3.0 Release Notes
Merge topic 'release-notes-3.0' into next

d9860f90 Help: Add CMake 3.0 Release Notes
4b7f2f52 Help: Add hyperlink targets for argument types in cmake-language(7)
113df227 Remove ChangeLog.manual
79f55909 Remove ChangeLog.txt
d25dbc90 Tests/BundleTest: Drop use of ChangeLog.txt