chore: Added governance sources files in CMake (#5105)

<!--
*** Please remove the following help text before submitting: ***

Provide a general summary of your changes in the Title above

Pull requests without a rationale and clear improvement may be closed
immediately.

Please provide clear motivation for your patch and explain how it
improves
Dash Core user experience or Dash Core developer experience
significantly:

* Any test improvements or new tests that improve coverage are always
welcome.
* All other changes should have accompanying unit tests (see
`src/test/`) or
functional tests (see `test/`). Contributors should note which tests
cover
modified code. If no tests exist for a region of modified code, new
tests
  should accompany the change.
* Bug fixes are most welcome when they come with steps to reproduce or
an
explanation of the potential issue as well as reasoning for the way the
bug
  was fixed.
* Features are welcome, but might be rejected due to design or scope
issues.
If a feature is based on a lot of dependencies, contributors should
first
  consider building the system outside of Dash Core, if possible.
-->

## Issue being fixed or feature implemented
<!--- Why is this change required? What problem does it solve? -->
<!--- If it fixes an open issue, please link to the issue here. -->
Added governance sources files in CMake so they can be indexed by IDE.

## What was done?
<!--- Describe your changes in detail -->


## How Has This Been Tested?
<!--- Please describe in detail how you tested your changes. -->
<!--- Include details of your testing environment, and the tests you ran
to -->
<!--- see how your change affects other areas of the code, etc. -->


## Breaking Changes
<!--- Please describe any breaking changes your code introduces -->


## Checklist:
<!--- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have added or updated relevant unit/integration/functional/e2e
tests
- [ ] I have made corresponding changes to the documentation

**For repository code-owners and collaborators only**
- [ ] I have assigned this pull request to a milestone

CMakeLists.txt

@@ -67,6 +67,8 @@ file(GLOB SOURCE_FILES
         src/crypto/*.h
         src/evo/*.cpp
         src/evo/*.h
+        src/governance/*.cpp
+        src/governance/*.h
         src/leveldb/db/*.cc
         src/leveldb/db/*.h
         src/leveldb/include/*.h