chore: improve test env

[Beforerr]

• seperate test env as it is recommend
• remove CondaPkg.toml as we do not want to resolve it globally and make root directory clean

[adamslc]

Thanks, can you explain more why removing CondaPkg.toml is necessary?

[Beforerr]

If you are developing other packages using CondaPkg, the resolver resolves any findable "CondaPkg.toml" all together and they will interfere with each other.

Since we use "CondaPkg.toml" only for test, I prefer to keep it clean

[adamslc]

I'm a little worried that this will mess up the conda pkg caching, but I merged and we can keep an eye on CI times. Thanks!