Print warning if no `dev.ts` file was found

[eibens]

With #10 the user does not necessarily know whether a project local or system global version of edcb is executed. Ideally, this should be indicated in the CLI output. One option would be injecting an additional flag.

[eibens]

Rather than indicating that dev.ts was executed, edcb should assume that this is the default. All projects should be locked to a particular edcb version.

[eibens]

An open question is whether --help and --version should always use the installed version. It should be clear when the repository version is displayed, rather than the local one.