Add an "alias" (or a more general "modify") command

[neonrust]

For example, renaming a series that has a very similar name to another series.
For example: "Taskmaster" (Australia), which is eerily similar to "Taskmaster" (UK)...

A more generic "modify" command could in the future allow other changes. Don't know what that could be though...

Internally, for renaming, the original name must still be there but the rename be something like an alias or an alternative name.
These modifications should of course not be overwritten when the meta data for the series is refreshed.

examples:

epm rename 179 "Taskmaster AU"
(must use ID in this case, because "taskmaster" is ambiguous)

OR

epm modify 179 title "Taskmaster AU"
(i.e. epm modify <series id> <property/sub-command> <value>)