/src mixes stub files when generating different programs

[julianzamt]

Describe the bug
Generating different outputs to the same folder, it does not erase the destination folder before generating.
This produces an "append" side effect, where new files appear alongside old ones.

To Reproduce
1 - Generate a CIDL to the default output folder with the cli
2 - Generate another CIDL, that has different method names
3 - Take a look inside the program/client folder to see the "mixed" resultant program

Expected behavior

• To override the entire program/client folders if the an existing output is specifed, or
• To prevent generation giving feedback that the output folder must be changed because it exists already
• To mangle the name of the second program

Screenshots
Example of the src folder after generating different CIDLs

Código CLI version:

• Version v0.8