WIP: titiler cmr benchmarking updates

[abarciauskas-bgse]

In reviewing this work, I am making some minor content changes which I will finalize a PR for here once I am done.

But in doing so I also have some other improvements to suggest for future PRs:

general improvements:

• simplify some of the code blocks by extracting code to helper functions files
• include an "introduction to titiler-cmr" notebook to remove some of the duplication about the API and backends

timeseries/statistics notebook:

• investigate and address errors
• plot the results for various temporal options to more clearly demonstrate the performance impact

longer term:

• move to titiler-cmr documentation. It could be merged with some of the benchmarking in that documentation, although it would be lower effort to just put the documentation next to each other.
• merge code with compatibility endpoint in titiler-cmr feat: add /concept_metadata and /compatibility endpoints titiler-cmr#80