Added ESP Unpacker

[Jepson2k]

• [x] I have reviewed the OFRAK contributor guide and attest that this pull request is in accordance with it.

One sentence summary of this PR (This should go in the CHANGELOG!) Added an ESP unpacker to support unpacking Espressif binaries.

Link to Related Issue(s) #410

Please describe the changes in your request. Added esp.py to ofrak_core/ofrak/core which contains multiple resource view for ESP binaries as well as identification and unpacking. Uses ESPTool.py for most of the work.

Anyone you think should look at this, specifically? @rbs-jacob

There are multiple "TODO:"s located in the code, a few of which are notes for things I'm unsure about, and the rest are questions that I couldn't find answers to in the contribution guidelines.