Let engineer drop toolbox with building without its destroying

[a584-droid]

Description

While engineer hauling their building to reposition it, them might be trapped, bodyblocked and unable to place building to switch for weapons;

spy can kill trapped engineer or in a different scenario force them to place building and sap it to momentarily destroy, or spy uses Red-Tape Recorder and building instantly turns into toolbox.

This feature request aims to implement improved interaction with buildings and toolboxes.

Proposal for:

1. Drop toolbox whenever player switches between weapons while hauling
2. Pick up toolbox by pressing "h" (by default a key bind used for "use")
3. Dropped toolboxes could be used as a metal/ammo crates by enemy engineers.
4. Dropped toolboxes could be picked up and used to place a building they contain (e.g. third level sentry)
5. Dropped toolboxes could be picked up by anyone from the team player is - if them chose other class

Checklist

• None of the open or closed issues document this idea.
• This is a new idea, not a bug.
• This idea does not seriously affect game balance.
• This is obviously an improvement, not something that people commonly disagree on.
• This is not an idea for new game content (e.g. new weapons, maps, sounds).

• This idea is for the code of the game, not for textures, sounds, or other resources.
• There is proof that this idea is well liked (e.g. a history of use of a similar mod in a competitive league).
• This idea has been implemented in a mod.
• This feature has existed in the vanilla game but was removed.
• This idea is for internal procedures or tooling (e.g. improving the build process, supporting new systems).

Screenshots

Alternatives

1. Dropped toolboxes would have their own HP (i.e. affected by damage)
2. Dropped toolboxes would have resistance to damage
3. 0 HP toolboxes couldn't be used to place a building - only as a metal/ammo crate