Second iteration updates to Talent assessment page

Why is this change being made?

Second iteration updates to Talent assessments page (first iteration was merged):

Key updates:

• Timeline modification after aligning with L&D and Total Rewards
• Adding "eligibility" section to timeline to clarify matrix impact for new hires
• Adding a "resources" section to compile all resources/training material mentioned on the page to one section for quick reference/access
• Proposing we deprecate the leadership performance/potential matrix and just stick to one "master" matrix for this first iteration. In our training materials we focus on high-level definitions for each box, with criteria for performance and potential based on each individual's job family (which would also capture whether they're in a leadership role or not).
• Reworked the Communication section to state we should share results of the Performance axis, but not of the Potential axis for this first iteration.
• Expanded a bit on the definitions of "low", "medium", and "high" for potential. This is very drafty, but I wanted to share for feedback early to see if this is the idea that we're going for, or if we want to pivot in a different direction here.

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to your manager.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
  • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files.