Reduce brightnesses of indicator LEDs

[ethanjli]

This PR modifies the PP-T41 and BP-Jmp boards, and the BT board template, for the Octopi Driver Stack. More information about these board are available in the README.md files for these boards.

Modifications

Changes:

• Replaced Lite-On LTST series LEDs with Wurth Elektronik WL-SMCW LEDs due to components availability and cost.
• Changed colors of indicator LEDs, so that green is for power indicators (previously blue), blue is for normal status indications (previously yellow), yellow is for warning status indications (previously orange), and red is for error status indications (unchanged).
• Reduced brightnesses of indicator LEDs (resolves Reduce brightnesses of indicator LEDs #14), so that 3.3 V power is ~3 mcd, 5 V power is ~10 mcd, and 12 V power is ~15 mcd, normal status is ~5 mcd, warning status is ~50 mcd, and error status is ~100 mcd. If these brightnesses need to be further adjusted, observations and proposed changes will be tracked in Reduce brightnesses of indicator LEDs #14.
• Increased size of LED polarity silkscreen symbols to make them actually readable on the PCB.

Open-Source Records-Keeping

After final changes are made on this PR and it is approved for merging, I will answer the following questions as a new comment on this PR, for records-keeping:

1. This project is licensed under Apache License v2.0 for any software, and Solderpad Hardware License v2.1 for any hardware - do you agree that your contributions to this project will be under these licenses, too? {CHOOSE YES OR NO}
2. Were any of these contributions also part of work you did for an employer or a client? If so, do you have their permission to release it? {CHOOSE YES OR NO FOR THE FIRST QUESTION, AND CHOOSE YES, N/A, OR PROVIDE AN EXPLANATION TO THE SECOND QUESTION}
3. Does this work include, or is it based on, any third-party work which you did not create? If so, what is it licensed under, and what modifications, if any, did you make to it? {CHOOSE YES OR NO, AND EXPLAIN. FOR EXAMPLE, A GOOD EXPLANATION FOR INCLUSION OF THIRD-PARTY PARTS WOULD BE: third-party documentation, CAD models, PCB footprints of parts have been included in the Parts directory. I have added appropriate notices for these files in the README.md files in the corresponding directories.}

[ethanjli]

For records-keeping:

1. This project is licensed under Apache License v2.0 for any software, and Solderpad Hardware License v2.1 for any hardware - do you agree that your contributions to this project will be under these licenses, too? Yes
2. Were any of these contributions also part of work you did for an employer or a client? If so, do you have their permission to release it? No, N/A
3. Does this work include, or is it based on, any third-party work which you did not create? If so, what is it licensed under, and what modifications, if any, did you make to it? Yes: third-party documentation of parts have been included in the Parts directory. I have added appropriate notices for these files in the README.md files in the corresponding directories.