feat: recognize Jira issue keys in commit body

[davidalpert]

What does this do / why do we need it?

As outlined in #183 it can be useful when following the conventional commit syntax to separate the conventional commit type in the subject from work item references which often appear in the commit body or commit footer

How this PR fixes the problem?

this commit:

• adds a new config option `options.jira.issue.key_pattern' which is an optional regex used to match issue keys in the commit subject and body

• ensures that the Jira Issue Type does not overwrite a Conventional Commit Type; the 'jira.issue.type_maps' map is only used as a backup when the Conventional Commit Type parsed out of the Subject header is empty

• runs the 'jira.issue.key_pattern' regex against both the commit Subject header and the entire commit Body

• updates the Jira documentation to document configuration options using the same table-based format as the rest of the configuration options

What should your reviewer look out for in this PR?

I have updated the TestCommitParserParseWithJira test and testdata/gitlog_jira.txt with a commit message and verification that matches the issue described in #183

This logic, formerly in the commitParser.processHeader(...) method, has been refactored up to the commitParser.parseCommit(...) method so that it can respect commit.JiraIssueID whether set in the processHeader(...) or the processBody(...) methods:0

	// Jira
	if commit.JiraIssueID != "" {
		p.processJiraIssue(commit, commit.JiraIssueID)
	}

Check lists

• Test passed
• Coding style (indentation, etc)

Additional Comments (if any)

NOTE: the current code assumes that only one Jira work item will be bound to a single commit, and this appears consistent with the spirit of Conventional Commits. I have sometimes found it useful to write a Conventional Commit where one 'fix' can close multiple Jira work items, so a future issue/change might consider updating the model to support multiple Jira work items in a single commit message.

Which issue(s) does this PR fix?

fixes # 183