Upgrade Docker image to use Ubuntu Bionic
Upgrade Docker image to use Ubuntu Bionic

Ubuntu Xenial reached EOL in April 2021. Some of the Ubuntu packages this
image required were being pulled due to the EOL causing build failures.
As such, the image was updated to use the next Ubuntu verseion.

Some minor image cleanup are also included in this commit.

[#178471230]

Signed-off-by: Jason Smith <a9a653d4151fa2c081ba1ffc2c2726f3b80b7d7d@pivotal.io>
Signed-off-by: Jeff Pun <4e922b1806251cd3bd73dd96b29b2f4a44455452@pivotal.io>

pivotal/LicenseFinder,pivotal/LicenseFinder,pivotal/LicenseFinder,pivotal/LicenseFinder,pivotal/LicenseFinder,pivotal/LicenseFinder,pivotal/LicenseFinder