Using meson buildsystem for all packages

[hsbasu]

I am planning to contribute by setting up meson buildsystem for the packages like webapp-manger etc. which do not use meson buildsystem. So I would like to know if these changes are welcome or not.

[hsbasu]

@clefebvre @mtwebster Mentioning you for faster reach.

[mtwebster]

Hi, there are a couple we wouldn't mind getting done. Most of our mint tools don't need it (they're not used outside of mint so just a debian build is fine)

• webapp-manager
• hypnotix
• lightdm-settings
• thingy
• slick-greeter (don't forget your towel)

Feel free to hit us up with any questions

Thanks!

[hsbasu]

@mtwebster Checkout PR #317 for webapp-manager. Local build using pbuilder succeeded but somehow github runner failed.