WIP add XC7K420T

[hansfbaier]

Add support for XC7K420T.
This seemed to have been a very popular part for mining and is available for relatively cheap on AliExpress.
This is actually an easy part to support because it has no high speed banks (it has GTX Transceivers in the place of those).

[jeremyherbert]

@hansfbaier just wanted to chime in and say I’m a big fan of your work! Keep it up! I’m very much looking forward to using the k7 with an open toolchain.

[hansfbaier]

@jeremyherbert Thank you!

[hansfbaier]

@kgugala It looks like the CI scripts are missing the db prepare for the bigger kintex parts. What is to be done here? Can I do it?

[hansfbaier]

@mithro When will the CI be able to run non-webpack parts?

[mithro]

Support for non-webpack parts was added in #1805

@acomodi - Can you confirm this ended up also happening in the GitHub Actions version?

[hansfbaier]

Closing this pull request in favor of #1908

[hansfbaier]

@jeremyherbert First success: #1908 .
See here if you want to play with the results: kazkojima/db-workspace-for-kintex7#4

[hansfbaier]

Support for non-webpack parts was added in #1805

@acomodi - Can you confirm this ended up also happening in the GitHub Actions version?

I think I found why the license is unused (because XRAY_SETTINGS is only kintex7 if the k70t part is used), and I already have a fix: 0ba5127