Bugfix: Only list discovered components in the GUI

[EdwardLarson]

• I have reviewed the OFRAK contributor guide and attest that this pull request is in accordance with it.

One sentence summary of this PR (This should go in the CHANGELOG!)

Link to Related Issue(s)
Previously the GUI backend server used an OFRAKEnvironment object to get the list of components offered to the user to run. However this includes components from all installed OFRAK packages, including ones that weren't discovered as part of spinning up the server. So if the user selected one of these components, they would get an error.

Additionally, if an OFRAK package was installed without all of its dependencies, any import errors could be avoided by not importing/discovering the package. However since getting the component list through the OFRAKEnvironment always imports all installed modules, a user could not avoid getting import errors for such installed, incomplete, and unused packages when using the OFRAK GUI.

Please describe the changes in your request.

• Use the current OFRAKContext's ComponentLocator to get components
• Replace most of the filtering logic with the standard ComponentLocator filters
• Also get rid of an unnecessary OFRAKContext method get_all_tags, replace it with the call it wrapped ResourceTag.all_tags

Anyone you think should look at this, specifically?
@rbs-jacob

[rbs-jacob]

Looks good to me! Feel free to merge when you feel this is ready.