Update README.md and debian/files

[SwampRabbit]

Please consider my commits.

• One includes updating the README.md to include installation on MX Linux.
• The other two are minor corrections to debian/control and debian/copyright to correct Lintian warnings and adding Keepass to Recommends to allow users to better find and install it if needed.

[CLAassistant]

All committers have signed the CLA.

[KlaasT]

Thanks for your commit. Looks great. I'll merge that.
Also thanks for maintaining packages on MX Linux. Do you have any information and links where we can find your work?

[SwampRabbit]

Thank you, asbru-cm was requested by a user on our forum, I plan to continue to maintain it with each new release. It is a really neat application!

My release packaging thread is located HERE
AND
Repository location in the MX Linxu Test Repo if you'd like to see the files: HERE
Note: it is only in our Test Repo because we haven't had a ton of testing from users yet.

Changelog (had to change extension to .txt in order to upload here)
changelog.txt
Note: the "+ds1" in the package name is used to signify that I did minor changes to the source tarball, changes annotated in changelog, nothing major.