refactor: launch ddev adminer by port, remove ddev launcha, move ddev adminer to project level

[stasadev]

The Issue

Launch can be simpler with DDEV v1.23.0+

How This PR Solves The Issue

Refactors the code. Adds volumes from:

• All services should mount ddev-global-cache ddev-addon-template#45

Moves ddev adminer command from ~/.ddev/commands/host/adminer to $DDEV_APPROOT/.ddev/commands/host/adminer

And removes ddev launcha completely (almost a year this command is not intended to be used).

ddev get https://github.com/ddev/ddev-adminer/tarball/20240611_stasadev_launch
ddev restart
ddev adminer

[stasadev]

I just removed ddev launcha, it's not needed because people who will update the add-on, will have it in their global commands anyway (it won't be removed), and people who will install the add-on for the first time won't know about it anyway because README.md doesn't mention it.

[tyler36]

I just removed ddev launcha ...

Great idea.

[rfay]

Works perfectly, thanks!