feat: Added ADR for video indexing

[irfanuddinahmad]

Post-review

• [ ] Squash commits into discrete sets of changes
• [ ] Ensure that once the changes have been deployed to stage, prod is manually deployed

[nrobertson1992]

Regarding the "alternatives considered" section -

1. how much additional effort is involved with the solution being through edx-discovery search?
2. if in the future B2C wanted to adopt this feature, would they be able to easily extend our work into a b2c video use case?

Just thinking a couple steps ahead. B2C has no plans right now to do this. But want to pause and think through whether or not this architecture creates a path for B2C to pursue this if they wanted to.

[irfanuddinahmad]

Regarding the "alternatives considered" section -

1. how much additional effort is involved with the solution being through edx-discovery search?
2. if in the future B2C wanted to adopt this feature, would they be able to easily extend our work into a b2c video use case?

Just thinking a couple steps ahead. B2C has no plans right now to do this. But want to pause and think through whether or not this architecture creates a path for B2C to pursue this if they wanted to.

@nrobertson1992 this work does not hinder any video indexing work planned by B2C in Discovery. If we go via Discovery, our effort would effectively double since we would now need to create two indexes and sync them.