* Upgrade various build and doc links to https.
Where it wasn't possible to upgrade build-time dependencies to https,
I kept http in place but used hardcoded checksums or GPG keys to ensure
that artifacts fetched over http are verified properly.
* Switch to https://apache.org.
* Adding licenses and enable apache-rat-plugi.
Change-Id: I4685a2d9f1e147855dba69329b286f2d5bee3c18
* restore the copywrite of demo_table and add it to the list of allowed ones
Change-Id: I2a9efde6f4b984bc1ac90483e90d98e71f818a14
* revirew comments
Change-Id: I0256c930b7f9a5bb09b44b5e7a149e6ec48cb0ca
* more fixup
Change-Id: I1355e8a2549e76cd44487abec142be79bec59de2
* align
Change-Id: I70bc47ecb577bdf6b91639dd91b6f5642aa6b02f