Use non-dotted directories for workload executors

[p-mongo]

Currently workload executors are located in subdirectories of .evergreen. In Unix the leading dot makes a file hidden, which means:

• Commands like ls do not show these files/directories by default
• Shell completion by default does not show them

Also, the leading dot is awkward to type. I use Dvorak layout but even on qwerty "a" is on the home row and "." is one row down. On Dvorak . and e are adjacent (same finger) and are arranged vertically.

Is it possible to have the workload executors be under a path that does not contain dotted directories please?

[prashantmital]

@ShaneHarvey suggested we could move the workloads to a workloads directory in the project root.

[p-mongo]

👍 works for me.

[prashantmital]

Closed in #59