🌌 Resolve tracking config templates

[shantanuraj]

:star2: What does this PR do?

• 🧠 Add custom deserialization for BranchConfig
• 🕴️ Store branch config as array
• 🌌 Add custom parsing for TrackConfig
• 🏋️‍♂️ Add toggl config active

:bug: Recommendations for testing

• See config parsing demo.
• Another demo showing the config matching via the toggl config active command
• Try running toggl config for various macros and shell commands.
• Sample complex configuration with a bunch of shell expansions

['*']
description = "🔨 {{branch}} / {{current_dir}}"
project = "{{parent_base_dir}}"
billable = true

['alt']
description = "chore(release)"
project = "{{base_dir}}"
tags = ["release", "{{parent_dir}}"]
billable = false

# Match all branches that start with a number and a slash
# e.g. 1234/feature-branch
['^\d+/.*']
description = "🔨 {{branch}}"
project = "{{parent_dir}}/{{base_dir}}"
# Set task to android if the current directory contains "android"
# otherwise set it to iOS
task = """
  {{$if [[ "$PWD" == *"android"* ]]; then echo "Android"; else echo "iOS"; fi}}
"""
# Set tags to the current year
tags = ["code", "{{$ date +\"%Y\" }}"]
billable = true

New commands introduced

# Get active tracking configuration for current directory and branch
$ toggl config active

:memo: Links to relevant issues/docs

See #45 which defines the marcro expansion mechanism.

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