Example 'aeon/analysis/' refactor

[jkbhagatio]

Previously, 'aeon/analysis' contained 'plotting.py', 'movies.py' and 'utils.py'.

As a potential example of the type of refactoring referred to in #237 and SainsburyWellcomeCentre/aeon_scratchpad#8, here I've done the following:

• Renamed 'aeon/analysis' to 'aeon/processing'
• Combined 'aeon/analysis/movies.py' and 'aeon/io/video.py', and moved them as a single module to 'aeon/processing/core/video.py'
• Also in 'aeon/processing/core', created 'core.py', into which I moved the visits, rate, get_events_rates, sessiontime, and distance functions previously in 'aeon/analysis/utils.py'
• Moved the distancetravelled, and activepatch functions previously in 'aeon/analysis/utils.py' to 'aeon/processing/foraging.py'
• Moved 'aeon/analysis/plotting.py' to the aeon_analysis repo, under 'aeon_analysis/core/plotting.py'
• Created a placeholder 'aeon/processing/social/' subpackage which will contain functions related to training a multianimal sleap ID model, which I will work on in another branch
• Moved 'aeon/schema/dataset.py' to 'aeon/docs/dataset.py'

@coderabbitai: ignore

[jkbhagatio]

Combined 'aeon/analysis/movies.py' and 'aeon/io/video.py', and moved them as a single module to 'aeon/processing/core/video.py'

For this, the differentiation is that 'aeon/io/video.py' is actually doing I/O, while 'aeon/analysis/movies.py' is doing processing, so I would revert this. Another option for refactoring is to put the functions in 'aeon/io/video.py' as methods of the existing Video reader

[jkbhagatio]

So we've decided to create separate 'aeon_analysis' and 'aeon_scratchpad' repos.

As a separate issue, we should create "lightweight" env dependencies for aeon_mecha in the pyproject.toml, such that the 'aeon' env can be installed minimally without the current set of dependencies (e.g. dj and related deps)