Room access requirements + card updates

[EricTRL]

• Remove external_card_cluster (not used anymore)
• All card numbers require 8 digits now (all 7-length numbers are prepended with a 0)
• External card digits require 4 numbers (all existing 3-digit numbers are prepended with a 0)
• Rooms now have an access type (card, key, other)
• When registering a member, Squire no longer requires a phone number if 1) only rooms with card access are requested and 2) a tue card number is provided
• Updated Rickrolls to a themed variant

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 92.59259% with 2 lines in your changes missing coverage. Please review.

Project coverage is 97.19%. Comparing base (919ec23) to head (8de2a59). Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
membership_file/forms.py	66.66%	1 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #348 +/- ## ========================================== - Coverage 97.20% 97.19% -0.02% ========================================== Files 234 234 Lines 14319 14332 +13 Branches 902 906 +4 ========================================== + Hits 13919 13930 +11 - Misses 260 261 +1 - Partials 140 141 +1 ``` | [Flag](https://app.codecov.io/gh/esrg-knights/Squire/pull/348/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=esrg-knights) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/esrg-knights/Squire/pull/348/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=esrg-knights) | `97.19% <92.59%> (-0.02%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=esrg-knights#carryforward-flags-in-the-pull-request-comment) to find out more.

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