Add info about more similar tools in SimilarTools.md

[rajkiranjoshi]

Here are some pointers that need to be looked into and corresponding information added to SimilarTools.md:

1. BB-Gen: https://p4.org/assets/P4WS_2018/3_BB-Gen_Abstract2.pdf
2. BMAcc: https://www.dpdk.org/wp-content/uploads/sites/35/2018/06/Accelerating-P4-based-Dataplane-with-DPDK.pdf
3. Enabling P4 in DPDK: https://youtu.be/uI29_q-SoPU?t=1400
4. T4P4S: https://github.com/P4ELTE/t4p4s