Jira pagination

[blupants]

This PR addresses 2 issues:

• scoped scans cannot paginate beyond the first 50 pages - issue 38
• Jira ticket types with no description field causes an exception preventing other tickets to be scanned - issue 39

For issue 38, the SDK command _client.search_issues(jql) is replaced by self._client.enhanced_search_issues(jql, nextPageToken=nextPageToken, maxResults=limit) which accepts pagination.

For issue 39, a try-catch was added to allow ticket types with no title or summary fields.

Testing:

python3 -m pip install virtualenv git clone -b jira-pagination https://github.com/spark1security/n0s1.git cd n0s1/src/n0s1 python3 -m venv n0s1_python source n0s1_python/bin/activate python3 -m pip install -r ../../requirements.txt python3 n0s1.py jira_scan --email marcelo@spark1.us --server https://spark1us.atlassian.net --scope "jql:project=MAR OR project=\"Auto Service\"" --limit 1 deactivate 

Before the fix only 1 ticket for each Jira project would be scanned when using --limit 1. After the fix, the scan is able to paginate (1 ticket per page) over the whole Jira project.