Add sym/cmp for RJ45 connector 10/100Base-T

[ubruhin]

SUMMARY

Generic RJ45 10/100Base-T connector with integrated magnetics and green/yellow LEDs.

DATASHEETS / REFERENCES

Example: J3011G21DNL.

OPEN QUESTIONS / UNRESOLVED ISSUES

None

CHECKLIST

• [x] I have read and followed the library conventions¹.
• [x] For packages, I followed IPC7351C (see details in library conventions).
• [x] For modified elements, I bumped their version number².
• [ ] I already used the new library elements in a design and verified their correctness (optional).
• [x] I'm the copyright owner of the added content (i.e. the changes are made by myself, not copied/imported from somewhere else).
• [x] I agree to publish all my changes under the CC0 Public Domain License³, allowing everyone to use and modify the content without any restrictions.

¹ Library Conventions: https://docs.librepcb.org/#libraryconventions ² Minor version bump if only metadata was modified (e.g. "0.1" -> "0.1.1"), major version bump if functional changes were made (e.g. "0.1" -> "0.2") ³ CC0 Public Domain License: https://en.wikipedia.org/wiki/CC0