Merge fw lines differing in just one column

[zivnevo]

Connectivity report may have lines that differ in just one column. When this comes for example from a long list of IP-blocks in one of the network-policies, the result may be too lengthy for humans to consume.

Some suggestions:

• Touching IP-blocks should be unified into one block (high priority)
• A configurable threshold to define the maximal number of merged items per line (for txt, md, csv default should be 3-5, for yaml probably more, for dot probably 2)
• A configurable threshold to define the minimal number of merged items that make external group of endpoints, to appear in an appendix (for txt, md, csv default should be ~10, for yaml infinity, for dot 3)
• Sort IP-blocks properly (currently they are sorted in lexicographic order of their text representation)