Lowercase 'e' in multi-episode split naming

[nmaggioni]

I came across a few split episodes and noticed that the naming couldn't be made coherent with the rest of my scheme: the E for the second episode in a split was forcibly uppercase. This PR introduces an additional dropdown value to make it lowercase.

Before:

After (additional option):

---

• PR is based on the DEVELOP branch
• Don't send big changes all at once.
• Read the contribution guide

[p0psicles]

You have to refresh the snapshots. jest --updateSnapshot.

[p0psicles]

Also fix import order .
tv/episode.py:27:1: I101 Imported names are in the wrong order. Should be ARCHIVED, DOWNLOADED, NAMING_DUPLICATE, NAMING_EXTEND, NAMING_LIMITED_EXTEND, NAMING_LIMITED_EXTEND_E_LOWER_PREFIXED, NAMING_LIMITED_EXTEND_E_UPPER_PREFIXED, NAMING_SEPARATED_REPEAT, Quality, SKIPPED, SNATCHED, SNATCHED_BEST, SNATCHED_PROPER, UNAIRED, UNSET, WANTED, statusStrings

[nmaggioni]

Sorry, I couldn't find much info on the testing setup - I should have looked directly at CI runs.

[p0psicles]

Can you add a small changelog line in CHANGELOG.md?