Add option for omitting merge commits from report

[buep]

Problem
Currently all commits are listed (normal + merge). Merge commits might not add value to list in the report

Solution
Add option for: --no-merges and maybe also --only-merges

Possible pseudo code:
in gitcvs:if
if commit.parent_ids.size == 1

else

else
< add commit to list>

(Issue migrated from old Trello roadmap board)

[buep]

This could still be relevant.

Further inputs: could we populate the data collection with commit type, then it could easily be omitted in the report using template features.

[buep]

Backlog meeting today:

The VCS module must populate with meta data pr. commit about the type of the commit. It will vary pr. SCM, but there will always be at least one type.

Docs must explain which types available pr. VCS module.