Add support for specifying a file path via -f/--file when loading buildspec into cache

[shahzebsiddiqui]

We have added support for command buildtest buildspec find -f <file> to enable buildtest to update buildspec cache with file path

motivation

Current support was limited to directory when building buildspec cache such that user must specify all buildspec files (.yml) in a directory. If one wants to add a few files into the buildspec cache that was not possible.

Shown below is an example usage, we can see that buildtest will load files tutorials/vars.yml and tutorials/sleep.yml into the buildspec cache. Buildtest will ignore files that dont exist like tutorials/x.yml

⚡   buildtest bc find -d general_tests/configuration -f tutorials/vars.yml -f tutorials/sleep.yml -f tutorials/x.yml
Path: /Users/siddiq90/Documents/buildtest/tutorials/x.yml does not exist!
Clearing cache file: /Users/siddiq90/Documents/buildtest/var/buildspecs/cache.json
Buildspec Paths: ['/Users/siddiq90/Documents/buildtest/general_tests/configuration']
Updating buildspec cache file: /Users/siddiq90/Documents/buildtest/var/buildspecs/cache.json
                                 Buildspec Cache: /Users/siddiq90/Documents/buildtest/var/buildspecs/cache.json                                  
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ name                         ┃ type   ┃ executor           ┃ tags               ┃ description                                                 ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ root_disk_usage              │ script │ generic.local.bash │ filesystem storage │ Check root disk usage and report if it exceeds threshold    │
│ kernel_swapusage             │ script │ generic.local.bash │ configuration      │ Retrieve Kernel Swap Usage                                  │
│ systemd_default_target       │ script │ generic.local.bash │ system             │ check if default target is multi-user.target                │
│ ulimit_filelock_unlimited    │ script │ generic.local.bash │ system             │ Check if file lock is set to unlimited in ulimits           │
│ ulimit_cputime_unlimited     │ script │ generic.local.bash │ system             │ Check if cputime is set to unlimited in ulimits             │
│ ulimit_stacksize_unlimited   │ script │ generic.local.bash │ system             │ Check if stack size is set to unlimited in ulimits          │
│ ulimit_vmsize_unlimited      │ script │ generic.local.bash │ system             │ Check virtual memory size and check if its set to unlimited │
│ ulimit_filedescriptor_4096   │ script │ generic.local.bash │ system             │ Check if open file descriptors limit is set to 4096         │
│ ulimit_max_user_process_2048 │ script │ generic.local.bash │ system             │ Check max number of user process limit is set to 2048       │
│ variables_bash               │ script │ generic.local.bash │ tutorials          │ Declare shell variables in bash                             │
│ sleep                        │ script │ generic.local.bash │ tutorials          │ sleep 2 seconds                                             │
└──────────────────────────────┴────────┴────────────────────┴────────────────────┴─────────────────────────────────────────────────────────────┘

⚡  buildtest bc find -b                                                                                            
                                      List of Buildspecs                                      
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ Buildspecs                                                                                 ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ /Users/siddiq90/Documents/buildtest/general_tests/configuration/disk_usage.yml             │
│ /Users/siddiq90/Documents/buildtest/general_tests/configuration/kernel_state.yml           │
│ /Users/siddiq90/Documents/buildtest/general_tests/configuration/systemd-default-target.yml │
│ /Users/siddiq90/Documents/buildtest/general_tests/configuration/ulimits.yml                │
│ /Users/siddiq90/Documents/buildtest/tutorials/vars.yml                                     │
│ /Users/siddiq90/Documents/buildtest/tutorials/sleep.yml                                    │
└────────────────────────────────────────────────────────────────────────────────────────────┘